Open Access

Neurofibromatosis type 1-associated tumours: Their somatic mutational spectrum and pathogenesis

  • Sebastian Laycock-van Spyk1,
  • Nick Thomas1,
  • David N. Cooper1 and
  • Meena Upadhyaya1Email author
Human Genomics20115:623

DOI: 10.1186/1479-7364-5-6-623

Received: 23 May 2011

Accepted: 23 May 2011

Published: 1 October 2011

Abstract

Somatic gene mutations constitute key events in the malignant transformation of human cells. Somatic mutation can either actively speed up the growth of tumour cells or relax the growth constraints normally imposed upon them, thereby conferring a selective (proliferative) advantage at the cellular level. Neurofibromatosis type-1 (NF1) affects 1/3,000-4,000 individuals worldwide and is caused by the inactivation of the NF1 tumour suppressor gene, which encodes the protein neurofibromin. Consistent with Knudson's two-hit hypothesis, NF1 patients harbouring a heterozygous germline NF1 mutation develop neurofibromas upon somatic mutation of the second, wild-type, NF1 allele. While the identification of somatic mutations in NF1 patients has always been problematic on account of the extensive cellular heterogeneity manifested by neurofibromas, the classification of NF1 somatic mutations is a prerequisite for understanding the complex molecular mechanisms underlying NF1 tumorigenesis. Here, the known somatic mutational spectrum for the NF1 gene in a range of NF1-associated neoplasms --including peripheral nerve sheath tumours (neurofibromas), malignant peripheral nerve sheath tumours, gastrointestinal stromal tumours, gastric carcinoid, juvenile myelomonocytic leukaemia, glomus tumours, astrocytomas and phaeochromocytomas -- have been collated and analysed.

Keywords

NF1 somatic mutations germline mutations pathogenesis tumorigenesis tumour benign malignant

Introduction

Neurofibromatosis type 1 (NF1) is a common auto-somal dominantly inherited tumour predisposition syndrome affecting 1/3,000-4,000 individuals worldwide [1, 2]. NF1 manifests a variety of characteristic features that include: hyperpigmentary abnormalities of the skin (café-au-lait macules and inguinal/axillary freckling), iris hamartomas (Lisch nodules) and the growth of benign peripheral nerve sheath tumours (neurofibromas) in the skin. Neurofibromas display many different subtypes and are associated with a variety of different clinical complications. Cutaneous neurofibromas are present in almost all adult NF1 patients [3]. Plexiform neurofibromas (PNFs), a more diffuse type of tumour, are present in 30-50 per cent of NF1 patients, and some 10-15 per cent of these benign tumours are transformed to malignant peripheral nerve sheath tumours (MPNSTs), the main cause of morbidity in NF1 [4]. Other NF1-associated clinical features include: skeletal abnormalities, such as tibial bowing or pseudoarthrosis; skeletal and orbital dysplasia; ostopenia/osteoporosis; aqueduct stenosis; macrocephaly; pectus excavatum; short stature; cardiovascular malformations; learning difficulties; and attention deficit disorder [1, 5].

Cancer represents the transformation of a cell whose growth is normally tightly controlled into one that is no longer under strict regulation, allowing the cell to multiply uncontrollably and even metastasize. This dramatic alteration in cellular control arises as a consequence of the accumulation of genetic and epigenetic changes: activated oncogenes speed up cell growth through the acquisition of gain-of-function mutations, whereas tumour suppressor genes (TSGs) promote progression by acquiring loss-of-function mutations. TSGs typically encode proteins involved in growth regulation, apoptosis initiation, cellular adhesion and DNA repair. In accordance with Knudson's two-hit hypothesis,[6] both alleles of a TSG must be inactivated for cellular transformation to occur. Typically, a patient will inherit a germline mutation in one TSG allele; a second-hit or somatic mutation then occurs post-fertilisation, thereby inactivating the remaining wild-type allele. Somatic mutation is thus a key event in cancers associated with TSG inactivation. Upon transformation, a cell may acquire many additional somatic mutations elsewhere in the genome, a few of which actively encourage tumour progression, designated as 'driver mutations', while most occur simply because of the increased number of cell replications and are usually of unknown biological consequence and so are designated as 'passenger mutations' [7].

The NF1 gene encodes neurofibromin, a negative regulator of the Ras/mitogen-activated protein kinase (MAPK) pathway. NF1 is a TSG and, consistent with Knudson's two-hit hypothesis, most patients carry (in all their cells) both a normal and a dysfunctional NF1 gene copy -- the latter harbouring the inherited (germline) mutation. It may be inferred that any tumours that arise will have acquired a second, somatic 'hit' that inactivates the normal NF1 allele, resulting in a complete loss of functional neurofibromin; a double hit (NF1-/-) is critical for NF1 tumorigenesis to occur [8, 9]. The question as to why only a few of these benign tumours eventually go on to become malignant, however, is still puzzling. Consistent with a central role for neurofibromin in cellular function, recent cancer genome sequencing studies have found that somatic NF1 gene mutations occur not only in association with NF1, but also in a number of other common cancers [1016].

In the context of NF1, few genotype-phenotype correlations are evident. Indeed, marked intrafamilial variation in terms of the clinical phenotype is common [5, 17]. The existence of such families is perhaps an indication of the importance of the second hit, since differences in the type and timing of somatic NF1 mutations may help to explain the variability in patient phenotype [18]. An appreciation of the spectrum of somatic mutations in NF1-associated tumours is therefore essential if we are to understand the molecular pathways involved -- itself a prerequisite for improvements in clinical treatment and the development of new therapeutics. This paper attempts to collate and review the spectrum of somatic NF1 mutations so far reported in NF1-associated tumours, with a view to assessing how they may serve to induce tumour growth and whether or not any genotype-phenotype correlation may be discerned

The NF1gene: Structure and function

The NF1 gene spans 283 kilobases (kb) of genomic DNA at 17q11.2 [19] and contains 61 exons [3, 20]. Neurofibromin, the 327 kDa protein encoded by the NF1 gene, is translated from a 12 kb messenger mRNA transcript, and has a number of alternative iso-forms [2124] (reviewed by Upadhyaya [25]). Neurofibromin contains 2,818 amino acids and is expressed at low levels in all cells, with higher levels in the nervous system. It functions as a negative regulator of active Ras, and of the associated Ras/MAPK signalling pathway. Neurofibromin contains a Ras-specific GTPase activating protein (GAP)-related domain which interacts directly with Ras, resulting in a conformational change that greatly stimulates the intrinsic GTPase activity of the Ras protein, thus significantly accelerating the conversion of the active GTP-bound form of Ras into its inactive GDP-bound form and effecting a net decrease in overall mitogenic signalling in the cell. As the Ras/MAPK cascade is critical for the control of cellular growth and differentiation, a lack of functional neurofibromin results in the constitutive activation of this central signalling pathway and in unregulated cell growth [26].

NF1 tumour biology

A variety of benign and malignant tumours are associated with NF1 and all involve tumorigenesis of neural crest-derived cells. Several murine models of neurofibromatosis have both successfully recapitulated much of the NF1 human phenotype and shown that NF1 is indeed a classical TSG [27, 28].

Neurofibromas exhibit extensive cellular heterogeneity, being composed of hyperproliferative Schwann cells (SCs), fibroblasts, mast cells and peri-neural cells. The SCs have been identified as the initiating cell type in neurofibromas and it is only in these cells that the NF1 gene becomes biallelically inactivated [29]. SCs are also the target for various growth factors known to stimulate neurofi-broma formation and growth. What is still not known, however, is the precise cell type within the SC cell lineage in which the somatic mutation occurs, the cell type which subsequently precipitates neurofibroma growth.

Cutaneous neurofibromas are thought to arise from skin-derived precursor cells (SKPs)[30] and these cells may well be under hormonal control, since most such tumours develop only during puberty [31]. Further, an increase in tumour size and number has also been noted during pregnancy, with some evidence for a postnatal decrease in tumour size [32, 33]. Almost all PNFs appear congenitally and it is thought that they are induced by a somatic NF1 mutation in SC precursors within the embryonic gestational window of 12.5-15.5 days [34]. It may be that this second hit does not render the SC precursor tumorigenic, but instead induces aberrant axonal segregation [35]. The extracellularly expressed transmembranal guidance protein, Sema4F, is strongly downregulated in neurofibromas and it has been suggested that this somehow indirectly promotes SC proliferation by rendering these cells more responsive to environmental signals, possibly through inhibition of axonal re-attachment [36]. In this way, the disruption of normal SC axonal interactions leads to neurofibroma development. An NF1-/+ haploinsufficient cellular environment is also considered necessary, probably because of the growth advantage conferred by the signalling deficiency due to reduced neurofibromin levels. Indeed, Le et al. [30] found that NF1 inactivation is necessary, although not sufficient, for neurofibroma formation, highlighting the importance of the tumour microenvir-onment. There is some evidence to indicate that the haploinsufficiency (NF1-/+) of the other supporting cells (fibroblasts, mast cells and perineurial cells) cooperates in neurofibroma development [37]. Additionally, it has been shown that NF1-/+ haploinsufficient mast cells readily migrate into preneo-plastic nerves, probably in response to Kit ligand, which exhibits four-fold increased levels in nullizygous SCs as compared to normal SCs [38, 39]. The molecular mechanisms underlying both PNF and cutaneous neurofibroma formation are becoming clearer, although the major details are still lacking. It would appear that the key to understanding neurofibroma formation lies in the elucidation of the precise molecular interactions of the haploinsufficient tumour microenvironment within the initial cell type harbouring the biallelically inactivated NF1 gene.

NF1-associated tumours

Cutaneous neurofibromas and PNFs

Neurofibromas are a characteristic feature of NF1 and have a diverse clinical presentation. They are classified as grade 1 tumours by the World Health Organization; they have multiple forms and may affect nerves in any body location. Tumours derived from skin sensory nerves are designated dermal or cutaneous neurofibromas, and usually present as discrete tumours that remain associated with a single nerve ending. Approximately 20-50 per cent of cutaneous neurofibromas exhibit loss of heterozygosity (LOH) at the NF1 locus and the majority of these lesions appear to be due to mitotic recombination [4042]. Tumours associated with larger nerves within the skin may spread within the dermis and appear as a diffuse mass. PNFs are much larger tumours, usually associated with major nerve trunks and nerve plexi. They are generally slow growing, may develop at both internal and external body locations and can often result in major disfigurement. PNFs occur in some 30-50 per cent of patients with NF1 and, although these tumours generally remain benign, some neurological impairment may result from their growth. Approximately 10-15 per cent of PNFs may become malignant.

While the genetic basis of neurofibroma development is still not fully understood, biallelic NF1 inactivation does seem to be required, as all tumour cells harbour both a constitutional and a somatic NF1 gene mutation [5]. About 70 per cent of PNFs have been reported to display LOH at the NF1 locus;[20] however, there is no obvious correlation between the type or location of germline NF1 mutations in NF1 patients and those of their somatic counterparts arising in their tumours [20].

Another interesting, although as yet unexplained, observation is that a few patients mildly affected by NF1 who never develop any cutaneous neurofibromas or PNFs have been shown to carry the same germline NF1 mutation (c.2970-2972delAAT) --namely, an in-frame 3-base pair (bp) deletion that leads to the loss of a methionine residue [3].

MPNSTs

Cells derived from within some 10-15 per cent of PNFs may eventually undergo malignant transformation into an MPNST. MPNSTs are aggressive and highly invasive soft tissue sarcomas with an annual incidence of 0.16 per cent in NF1 patients, compared with only 0.001 per cent in the normal population,[43] and with a lifetime risk of 8-13 per cent in NF1 individuals [44, 45] (reviewed by Upadhyaya [4]). This form of malignancy represents a major cause of morbidity and mortality in NF1. Malignant transformation usually appears to evolve from within a pre-existing PNF [46]. The distinction between benign PNFs and MPNSTs has been sensitively visualised by non-invasive [18F]-2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) imaging,[47] suggesting a potential role for FDG-PET-based non-invasive imaging in future diagnostic tests. The aberrant molecular pathways that underlie this malignant transformation are still largely unknown, and considerable effort is being directed towards elucidating the molecular defects involved.

NF1 patients carrying large (usually 1.4-megabase [Mb]) genomic deletions (which remove the entire NF1 gene plus a variable number of flanking genes) have an increased risk of MPNST development in certain patient groups [48, 49]. Indeed, over 90 per cent of MPNSTs have been found to harbour large NF1 somatic deletions [20]. More recently, significantly increased frequencies (relative to the general NF1 population) of PNFs, subcutaneous neurofibromas, spinal neurofibromas and MPNSTs have also been reported in association with molecularly ascertained 1.4 Mb type-1 NF1 deletions [50]. The MPNST-associated deletion breakpoints have been found not to involve the paralogous repetitive sequences that are involved in most germline NF1 deletions [18]. The smallest common region of somatic deletion overlap is, however, restricted to approximately the same ~2.2 Mb interval that contains most of the genes deleted in recurrent constitutional NF1 deletions [51].

Although it is clear that biallelic NF1 gene inactivation is required for transformation to occur, mutations at the NF1 locus are insufficient to explain the process of tumorigenesis, as most benign neurofibromas also exhibit such biallelic NF1 inactivation. The best evidence for the involvement of other loci relates to the tumour protein 53 gene (TP53), for which several different mutations have been found in MPNSTs that have not been reported in benign neurofibromas [4, 20, 52, 53]. Mice with heterozygous mutations in both their Nf1 and Tp53 genes developed malignancy,[27, 54] an indication, perhaps, that TP53 loss is critical to transformation. The homozygous loss of the cyclin-dependent kinase inhibitor 2A gene (CDKN2A), which encodes p16INK4A and p14ARF, has also been associated with NF1 malignancy [5557]. Another recent report has indicated that phosphatase and tensin homologue deleted on chromosome 10 gene (PTEN) dosage, and/or phosphatidylinositol 3-kinase/AKT8 virus oncogene cellular homologue (PI3K/AKT) pathway activation, may be rate-limiting steps in NF1 malignant transformation [58]. As yet, however, no characteristic gene expression signature has been defined for MPNST development, although several cell-cycle and signalling regulation genes: -- cyclin-dependent kinase inhibitor (CDKN2A); tumour protein 53 (TP53); retinoblastoma 1 (RB1); epidermal growth factor receptor (EGFR); CD44 antigen (CD44); platelet-derived growth factor receptor alpha (PDGFRA); hepatocyte growth factor (HGF); proto-oncogene protein (C-MET) and transcription factor (SOX9) -- are frequently deregulated [4].

Recent studies of the micro-RNA expression profile of MPNSTs have expanded the pathogenic spectrum associated with this tumour. For example, microRNA-34a (miR-34a) is downregulated in MPNSTs; this microRNA (miRNA) regulates many cell cycle genes and is also upregulated by p53, suggesting that TP53 loss would lead to down-regulation of miR-34a and possibly several other miRNAs. This implies that this could be a critical event in malignant transformation [59]. In similar vein, miR-10b has been reported to be upregulated in SCs from NF1 tumours, while miR-10b inhibition reduced MPNST cell proliferation, migration and invasion [60]. NF1 mRNA is also a specific target for miR-10b,[60] indicating that these miRNAs represent potential therapeutic targets.

Spinal neurofibromas

About 40 per cent of NF1 patients present with tumours involving their spinal nerves. This is especially marked in individuals affected with familial spinal neurofibromatosis (FSNF), a variant form of NF1 in which bilateral tumours involving multiple spinal nerve roots are often the only manifestation of NF1 [6163]. Patients with FSNF have been reported to be significantly more likely to harbour missense or splice-site germline mutations compared with patients with classical NF1 [64]. A recent study of the NF1 locus found LOH in eight of 22 spinal tumours analysed, with most (75 per cent) of this LOH being due to mitotic recombination rather than genomic deletions [64].

Gastrointestinal stromal tumours (GISTs)

GISTs are the most common mesenchymal tumours of the gastrointestinal tract. Although most GISTs harbour activating somatic mutations of KIT and PDGFRA, the absence of such mutations from NF1-associated GISTs (NF1-GISTs) is probably indicative of a different pathogenetic mechanism. In NF1, the majority (60 per cent) of GISTs develop in the small intestine, whereas sporadic non-NF1 GISTs mainly involve the stomach [65].

Somatic NF1 mutations have been identified in the interstitial cells of Cajal (ICC) throughout the gastrointestinal tract and in NF1-GISTs lacking KIT or PDGRA mutations [66]. Increased signalling through the Ras/MAPK pathway has also been shown to occur in NF1-GISTS, as opposed to sporadic GISTs. This would seem to indicate that a decrease in neurofibromin level, in the presence of normal c-KIT and PDGFRA levels, leads to tumour formation. It also suggests that NF1 haploinsufficiency is required for ICC hyperplasia, again demonstrating that, although a somatic NF1 mutation is absolutely necessary, it is not sufficient to permit tumorigenesis: additional genetic events required. These observations concur with Knudson's two-hit hypothesis. Somatic inactivation of the NF1 gene through gene deletion; intragenic deletion; and LOH through mitotic recombination have also been described [66, 67].

Gastric carcinoid

Gastric carcinoid tumours are associated with multiple endocrine neoplasia, atrophic gastritis and pernicious anaemia but are very rare in NF1 [17]. LOH at the NF1 locus has been demonstrated in a gastric carcinoid tumour derived from an NF1 patient [67].

Juvenile myelomonocytic leukaemia (JMML)

Young NF1 patients are at particular risk of developing JMML,[68] a clonal haematopoietic disorder characterised by hypersensitivity (at least in vitro) to granulocyte-macrophage colony-stimulating factor (GM-CSF). Moreover, some 15-20 per cent of JMML patients harbour a somatic NF1 inactivating mutation, even though most exhibit no other NF1 symptoms [69]. Patients may also carry inactivating mutations of other genes, with a recent study identifying that 70-80 per cent of mutations involve genes in the Ras/MAPK pathway, including one tyrosine-protein phosphatase non-receptor type 11 (PTPN11), neuroblastoma RAS viral oncogene homologue (NRAS), and v-Ki-ras2 kirsten rat sarcoma viral oncogene homologue (KRAS) as well as NF1 genes [70]. Additional somatic mutations have also been reported in the casitas B-lineage lym-phoma (CBL) and additional sex combs-like 1 (ASXL1) genes [71]. In most cases, the NF1 gene is lost either via LOH or by compound heterozygous microlesions,[72] which lead to a complete loss of neurofibromin and hyperactive signalling through the Ras/MAPK pathway. LOH may occur through 1.2-1.4 Mb interstitial deletions mediated by low copy number repeat (LCR) elements that flank the NF1 gene [73]. LOH through uniparental interstitial isodisomy (50-52.7 Mb) of chromosome 17 through double mitotic recombination, in an as-yet-unknown initiator cell, has also been reported [72]. The rarity of such events may indicate the existence of a selective advantage, conferred upon the NF1-/- cells, which might explain the propensity of NF1 patients to develop leukaemia [74].

Astrocytomas (ACs)

Optic pathway tumours or ACs are found in ~15 per cent of paediatric NF1 patients,[75] with the complete loss of neurofibromin evident in NF1-associated optic gliomas [76]. Approximately 84 per cent of NF1-associated ACs also exhibit LOH in the NF1 region, with many tumours also exhibiting LOH of 17p, suggesting the likely role of TP53 -- or other 17p13-located genes -- in AC formation [77]. As with MPNSTs, biallelic somatic NF1 mutation in ACs is, again, apparently insufficient to induce transformation.

Phaeochromocytomas (PCs)

PCs are extremely rare tumours, with only one to six cases observed per million individuals. PCs develop from neural crest-derived chromaffin cells, and the tumour cells produce and release catechol-amines, which cause hypertension and flushing. These are tumours of the adrenal medulla and are primarily associated with mutations of the Ret proto oncogene (RET), von Hippel-Lindau (VHL), succinate dehydrogenase complex, subunit B (SDHB), succinate dehydrogenase complex, subunit C (SDHC), and succinate dehydrogenase complex, subunit D (SDHD) genes, although LOH in the NF1 region, as well as LOH of other loci on both 17q and 17p, have been observed [78, 79].

Glomus tumours

Glomus tumours are small ( < 5 mm), benign, but often very painful tumours that develop specifically within the highly innervated glomus body located at the end of each digit. These tumours appear to develop from a-smooth muscle actin-positive cells that have undergone biallelic NF1 inactivation, resulting in increased Ras/MAPK activity [80]. The somatic NF1 mutations often differ between glomus tumours, indicating highly specific tumori-genic events. Brems et al[80]. have suggested that glomus tumours, although rare, should now be recognised as an integral component of the NF1 spectrum of disease.

The somatic mutational spectrum of NF1-associated tumours

A review of all published -- and the authors' many unpublished -- somatic NF1 alterations associated with NF1 tumours was undertaken to gain a better appreciation of NF1 tumorigenesis. As of July 2010, at least 577 different somatic NF1 gene changes had been reported in different NF1-associated tumours, with more than half (323/577; 56 per cent) corresponding to LOH in the NF1 gene region, some involving much larger regions of chromosome 17 (Table S1 (Table 4)). The level of LOH detected also differs between cutaneous neurofibromas, PNFs and MPNSTs (40 per cent, 79 per cent and 85 per cent, respectively; Table 1). Table 2 provides the incidence of LOH in the other tumour types, where appropriate evidence has been obtained by multiplex ligation-dependent probe amplification (MLPA), fluorescence in situ hybridisation (FISH) etc; 78 per cent (28/36) of cutaneous neurofibromas, 44 per cent (11/25) of PNFs and 16 per cent (5/31) of MPNSTs display LOH resulting from mitotic recombination. Some 79 per cent (15/19) of the JMML samples that exhibited LOH appear to have lost the entire 17q arm through mitotic recombination, perhaps indicating a significant correlation with this tumour type.
Table S1

Summary of germline mutations and loss of heterozygosity (LOH) in NF1-associated tumours

Patient ID

Germline mutation

Type of germline mutation

LOH

LOH markers

Predicted extent of LOH

Evidence for genomic deletion? MLPA/CGHarrayCGH/FISH

Probable mechanism

No. samples with LOH

Reference

Dermal neurofibromas

        

T190.2

Exon 2 and 3 deletion

Two exon deletion

Yes

E5 RFLP, I12b,

IVS27A28.4, J1/J2,

EVI20, IVS38GT53.0,

3'NF1, C7CT1/2

(3'UTR), EW206,

EW207, D17S798,

D17S1868

NF1 and 3' flanking region

MLPA

Deletion

5/23

1

T190.6

  

Yes

E5 RFLP, I12b,

IVS27A28.4, J1/J2,

EVI20, IVS38GT53.0,

3'NF1, C7CT1/2

(3'UTR), EW206

NF1 and 3' flanking region

MLPA

Deletion

  

T190.11

  

Yes

E5 RFLP, I12b,

IVS27A28.4, J1/J2,

EVI20, IVS38GT53.0,

3'NF1, C7CT1/2

(3'UTR)

NF1 and 3' flanking region

MLPA

Deletion

  

T190.17

  

Yes

E5 RFLP, I12b,

IVS27A28.4, J1/J2

Intragenic NF1

MLPA

Deletion

  

T190.18ii

  

Yes

E5 RFLP

Intragenic NF1

MLPA

Deletion

  

T206.1

Ex4b:

c.499_502delTGTT;

p.C167GnfsX9

4 bp

deletion

(FS)

 

LOH

 

NIA

  

Unpublished data, Cardiff

T206.2

   

LOH

     

T206.3

   

LOH

     

L002_3

Ex9: c.1246C > T;

p.Arg416X

Nonsense

Yes

rs29001484, rs4583306,

NF1 germline mutation,

rs2055091, rs11869264

NF1

Array CGH

Deletion

6/28

2

L002_5

  

Yes

rs29001484, rs4583306,

NF1 germline mutation,

rs2055091, rs11869264

NF1

Array CGH

Mitotic recombination

  

L002_12

  

Yes

rs29001484, rs4583306,

NF1 germline mutation,

rs2055091, rs11869264

NF1

Array CGH

Mitotic recombination

  

L002 C

  

Yes

NS

 

NIA

 

3/38

3

T473.1A

Ex10b: c.1413-

1414delAG;

p.Lys471AsnfsX4

2 bp

deletion

(FS)

Yes

HHH202, J1J2, IVS27,

EV120, IVS38

NF1

MLPA

Mitotic recombination

22/89

4

T473.1C

  

Yes

HHH202, J1J2, EV120

NF1

MLPA

Mitotic recombination

  

T473.3

  

Yes

J1J2, EV120, IVS38

NF1

MLPA

Mitotic recombination

  

T473.5

  

Yes

HHH202, J1J2, EV120,

IVS38

NF1

MLPA

Mitotic recombination

  

T473.7

  

Yes

J1J2, EV120

NF1

MLPA

Mitotic recombination

  

T473.8

  

Yes

HHH202, J1J2, EV120,

IVS38, 3'NF1, EW207,

D17S949, D17S1822

NF1 and 3'

flanking

region

MLPA

Mitotic recombination

  

T473.10

  

Yes

J1J2, EV120, IVS38

NF1

MLPA

Mitotic recombination

  

T473.14

  

Yes

J1J2, EV120, IVS38,

3'NF1, EW207,

D17S949, D17S1822

NF1 and 3'

flanking

region

MLPA

Mitotic recombination

  

T473.15

  

Yes

J1J2, EV120, IVS38,

3'NF1

NF1

MLPA

Mitotic recombination

  

T473.16

  

Yes

J1J2, EV120, IVS38,

3'NF1, EW207,

D17S949,

D17S1822

NF1 and 3'

flanking

region

MLPA

Mitotic recombination

  

T473.21

  

Yes

J1J2, EV120

NF1

MLPA

Mitotic recombination

  

T473.35

  

Yes

EV120, IVS38

Intragenic NF1

MLPA

Mitotic recombination

  

T473.30

  

Yes

J1J2, EV120, IVS38,

3'NF1, EW207,

D17S949

NF1 and 3'

flanking

region

MLPA

Mitotic recombination

  

T473.32

  

Yes

J1J2, EV120

Intragenic NF1

MLPA

Mitotic recombination

  

T473.34

  

Yes

EV120, IVS38

Intragenic NF1

MLPA

Mitotic recombination

  

T225.1

Ex10b deletion [MLPA]

Single exon deletion

 

LOH

 

NIA

  

Unpublished data, Cardiff

T225.3

   

LOH

     

T68.2

Deletion exons 10b-19b

Partial gene deletion

Yes

UT172 - I38 206,207

Exon 5-3' region

NIA

  

Unpublished data, Cardiff

T68.3

  

Yes

UT172 - I38 206,207

Exon 5-3' region

    

CLJ1N

Ex13: c.2041C > T;

p.Arg681X

Nonsense

Yes

NF1, D17S1800

NF1 and 3' flanking region

NIA

 

32/126

5, 6, 7

CLJ2N

  

Yes

D17S33, D17S1294,

NF1, D17S1800,

D17S798, D17S250,

D17S787, D17S802

Majority of 17q

    

T170.3

Ex13: c.2041C > T;

p.Arg681X

Nonsense

 

LOH

 

NIA

  

Unpublished data, Cardiff

T170.2

   

LOH

     

ABA1N

Ex13: c.2251 + 2T > C

Splice site

Yes

DS17S1824, D17S841,

D17S1294, D17S1863,

NF1, D17S1800,

D17S1880, D17S798,

D17S250, D17S787,

D17S802, D17S784,

D17S928

Majority of 17q

NIA

 

32/126

5, 6, 7

ABA2N

  

Yes

DS17S1824, D17S841,

D17S1294, D17S1863,

NF1, D17S1800,

D17S1880, D17S798,

D17S250, D17S787,

D17S802, D17S784,

D17S928

Majority of 17q

   

5, 6, 7

T436

Ex17: c.2875C > T;

p.Glu959X

Nonsense

Yes

IVS27, EV120, IVS38

Intragenic NF1

MLPA

Mitotic recombination

22/89

4

T439

  

Yes

IVS27, EV120, IVS38

Intragenic NF1

MLPA

Mitotic recombination

  

T440

  

Yes

IVS27, EV120, IVS38

Intragenic NF1

MLPA

Mitotic recombination

  

T444

  

Yes

HHH202, J1J2, IVS27,

EV120, IVS38, 3'NF1

NF1 and flanking regions

MLPA

Mitotic recombination

  

T446

  

Yes

IVS27, EV120, IVS38

Intragenic NF1

MLPA

Mitotic recombination

  

T448

  

Yes

HHH202, J1J2, IVS27,

EV120, IVS38, 3'NF1

NF1 and flanking regions

MLPA

Mitotic recombination

  

T454

  

Yes

IVS27, EV120, IVS38

Intragenic NF1

MLPA

Mitotic recombination

  

EAD1N

Ex20: c.3419C > G;

p.Ser1140X

Nonsense

Yes

NS

 

NIA

 

32/126

5, 6, 7

EAD2N

         

CSG3N

Ex21: c.3525_3526delAA;

p.Arg1176GlufsX17

2 bp deletion (FS)

Yes

D17S1824, D17S1294,

NF1, D17S1800,

D17S1880, D17S798

NF1 and flanking regions

NIA

 

32/126

5, 6, 7

CSG38N

  

Yes

NF1

NF1

    

CSN1N

  

Yes

D17S1294, NF1,

D17S1880, D17S798,

D17S250, D17S787,

D17S784, D17S928

Majority of 17q

    

CSG1N

  

Yes

D17S1294, NF1,

D17S1800, D17S1880,

D17S798, D17S250,

D17S787, D17S802

Majority of 17q

    

CSG2N

  

Yes

DS17S1824, D17S1294,

NF1, D17S1800,

D17S1880, D17S798,

D17S250, D17S787,

D17S802

Majority of 17q

    

CSG4N

  

Yes

DS17S1824, D17S1294,

NF1, D17S1800,

D17S1880, D17S798,

D17S250, D17S787,

D17S802

Majority of 17q

    

CSG5N

  

Yes

DS17S1824, D17S1294,

NF1, D17S1800,

D17S1880, D17S798,

D17S250, D17S787,

D17S802

Majority of 17q

    

CSG21N

  

Yes

DS17S1824, D17S1294,

NF1, D17S1800,

D17S1880, D17S798,

D17S250, D17S787,

D17S802

Majority of 17q

    

CSG25N

  

Yes

D17S1294, NF1,

D17S1800, D17S1880,

D17S798, D17S250,

D17S787, D17S802

Majority

of 17q

    

CSG42N

  

Yes

D17S1294, NF1,

D17S1800, D17S1880,

D17S798, D17S250,

D17S787, D17S802

Majority of 17q

    

CSG51N

  

Yes

DS17S1824, D17S1294,

NF1, D17S1800,

D17S1880, D17S798,

D17S250, D17S787,

D17S802

Majority

of 17q

FISH

Mitotic recombination

  

CSG52N

  

Yes

D17S33, DS17S1824,

D17S1294, NF1,

D17S1800, D17S1880,

D17S798, D17S250,

D17S787, D17S802

Majority

of 17q

NIA

   

CSG62N

  

Yes

NS

     

T177

Ex23.1: c.3916 C > T;

p.Arg1306X

Nonsense

 

LOH

 

NIA

  

Unpublished data, Cardiff

T213

   

LOH

     

NF44

UHG_1

Ex27a: c.4515-2A > T

Splice site

Yes

NF1 germline mutation,

rs9891455

NF1

Array CGH

Deletion

6/28

2

NF44

UHG_41

  

Yes

rs1018190

NF1

Array CGH

Deletion

  

T106.1

Ex37: c.6791dupA;

p.Tyr2264X

1 bp

insertion

(FS)

Yes

IVS38, 3'NF1-1

 

NIA

  

Unpublished data, Cardiff

T106.5

  

Yes

I41 - C3

3' UTR

    

T106.6

  

Yes

J1J2, EVI20, I38, I41,

C3C7, 206, 207

     

T210.2

Ex42: c.7458delC;

p.Tyr2487IlefsX5

1 bp

deletion

(FS)

   

30% WG

  

Unpublished data, Cardiff

T210.4

     

30% WG

   

T210.8

     

30% WG

   

T210.4

     

E8: 30% WG

   

T210.5

     

E8: exon duplication

   

HT1335

Ex4c: c.7237C > T;

p.Gln2413X

Nonsense

   

E16: del

  

Unpublished data, Cardiff

T128.30

Ex6: c.784C > T;

p.Arg262Cys

Missense

Yes

 

3' UTR to

3' region

NIA

  

Unpublished data, Cardiff

T192.4

Deletion of exons 6-27a [MLPA]

Multi-exon deletion

 

LOH: J1J2, EV120,

HHH202,

    

Unpublished data, Cardiff

p062

Ex7: c.910C > T;

p.Arg304X

Nonsense

 

LOH (6 samples)

 

Deletion (2 samples)

  

Unpublished data, Cardiff

p082

Ex7: c.910C > T;

p.Arg304X

Nonsense

 

LOH (5 samples)

 

Deletion(5 samples)

   

ACF1N

Ex7: c.910C > T;

p.Arg304X

Nonsense

Yes

D17S841, D17S1294,

D17S1863, NF1,

D17S1880, D17S798,

D17S250, D17S802,

D17S784

Majority of 17q

FISH

Mitotic recombination

32/126

5, 6, 7

MIGS1N

Ex7: c.910C > T;

p.Arg304X

Nonsense

Yes

D171863, NF1,

D17S1800, D17S1880

NF1 and flanking regions

NIA

 

32/126

 

CAG1N

Ex7: c.979delCinsTT;

p.Leu327PhefsX3

Indel (FS)

Yes

NF1

Intragenic NF1

NIA

 

32/126

 

CAG3N

Ex7: c.979delCinsTT;

p.Leu327PhefsX3

Indel (FS)

Yes

NS

 

NIA

 

32/126

 

T199

Ex7: c.983_984delGT;

p.Cys324X

2 bp

deletion

(FS)

Yes

IVS12, J1J2

 

NIA

  

Unpublished data, Cardiff

NF56-2

Ex9: c.1246C > T;

p.Arg416X

Missense

Yes

Pin 1, RsaI, AluI, Pin 28,

530, NF1 3'UTR, Mfd

15

NF1 and flanking regions

NIA

 

1/6

8

T197A

Ex10a: c.1318C > T

p.Arg440X

Nonsense

 

LOH?

    

Unpublished data, Cardiff

CLT1N

Ex12a:

c.1754_1757delTAAC;

p.Thr586SerfsX19

4 bp deletion (FS)

Yes

D17S841, D17S1863,

NF1, D17S1800,

D17S1880, D17S787,

D17S802

Majority of 17q

  

32/126

 

p022

Ex12a:

c.1756_1759delACTA;

p.Thr586ValfsX18

4 bp deletion (FS)

 

LOH (9 samples)

 

Deletion (2 samples)

  

Unpublished data, Cardiff

p020

Ex13: c.2041C > T;

p.Arg681X

Nonsense

 

LOH (2 samples)

 

Deletion

(0 samples)

   

T141.5

Ex13: c.2233delA;

p.Ser745AlafsX2

1 bp

deletion

(FS)

Yes

202, 12b, IVS27, IVS38,

3'NF1

    

Unpublished data, Cardiff

p103

Ex15: c.2338A > C;

p.Thr780Pro

Missense

 

LOH (10 samples)

 

Deletion(3 samples)

  

Unpublished data, Cardiff

T22

Ex17: c.2851-2A > G

Splice site

Yes

 

3'UTR to 3' flanking regions

   

Unpublished data, Cardiff

NF253-UHG E

Ex17: c.2851-2A > G

Splice site

Yes

Not specific

 

NIA

 

3/38

3

L005 A

Ex18: c.3113 + 1G > A

Splice site

       

319T1

Ex19b: c.3208C > T;

p.Gln1070X

Nonsense

Yes

NF-exon5

Intragenic NF1

  

2/15

9

p023

Ex21: c.3525_3526delAA;

p.Arg1176SerfsX18

2 bp deletion (FS)

 

LOH (14 samples)

 

Deletion (5 samples)

  

Unpublished data, Cardiff

p011

Ex22: c.3826C > T;

p.Arg1276X

Nonsense

 

LOH (5 samples)

 

Deletion (1 sample)

   

MASG2N

Ex22: c.3870 + 1G > T

Splice site

Yes

NF1, D17S1880,

D17S798, D17S250,

D17S787

Majority of 17q

FISH

Mitotic recombination

32/126

5, 6, 7

T171

Ex23.2: c.4084 C > T;

p.Arg1362X

Nonsense

 

LOH

    

Unpublished data, Cardiff

p104

Ex25: c.4309G > T;

p.Glu1436X

Nonsense

 

LOH (3 samples)

 

Deletion

(0 samples)

  

Unpublished data, Cardiff

p078

Ex27a: c.4537C > T;

p.Arg1513X

Nonsense

 

LOH (6 samples)

 

Deletion

(0 samples)

   

p084

Ex27a: c.4572C > G;

p.Tyr1524X

Nonsense

 

LOH (2 samples)

 

Deletion

(0 samples)

   

p102

Ex29: c.5242C > T;

p.Arg1748X

Nonsense

 

LOH (5 samples)

 

Deletion

(2 samples)

   

p055

Ex30: c.5710 G > T;

p.Glu1904X

Nonsense

 

LOH (1 sample)

 

Deletion

(0 samples)

   

EMN1N

Ex30:

c.5749 + 332A > G

Splice site

Yes

NF1, D17S1800

NF1 and 3' flanking region

  

32/126

5, 6, 7

p027

Ex33: c.6226delG;

p.Ala2076GlnfsX13

1 bp deletion (FS)

 

LOH (1 sample)

 

Deletion (0 samples)

  

Unpublished data, Cardiff

p052

Ex37: c.6791_6792dupA;

p.Tyr2264X

1 bp duplication (FS)

 

LOH (1 sample)

 

Deletion (1 sample)

   

T23.6

Ex41:

c.7268_7269delCA;

p.Thr2423SerfsX2

2 bp deletion (FS)

Yes

EVI20, I38, I41, C3

 

NIA

  

Unpublished data, Cardiff

T100

Ex41: c.7267dupA;

p.Thr2426X

1 bp duplication (FS)

Yes

 

I38 to 3'UTR

   

Unpublished data, Cardiff

T164.1

Ex41: c.7285 C > T;

p.Arg2429X

Nonsense

 

LOH

    

Unpublished data, Cardiff

MAR2N

NI

NI

Yes

NF1, D17S1800

NF1 and 3' flanking region

NIA

 

32/126

5, 6, 7

MOPT2N

NI

NI

Yes

D17S1824, D17S1294,

D171863, NF1,

D17S1800, D17S1880

NF1 and flanking regions

    

NGL1N

NI

NI

Yes

D17S841, D17S1294,

NF1, D17S1800,

D17S1880, D17S798,

D17S250, D17S802,

D17S784, D17S928

Majority of 17q

    

JRR2N

NI

NI

Yes

D17S1294, D17S1863,

NF1, D17S1800,

D17S1880, D17S798,

D17S250, D17S787

Majority of 17q

    

SLC1N

NI

NI

Yes

D17S33, DS17S1824,

D17S841, D17S1294,

NF1, D17S1880,

D17S798, D17S250,

D17S784, D17S928

Majority of 17q

    

HT1377.1

NI

NI

Yes

     

Unpublished data, Cardiff

HT1377.2

NI

NI

Yes

  

NIA

   

T109.4

NI

NI

Yes

I38, I41, 206

3' region

    

T167.c

NI

NI

Yes

IVS27, IVS38, 3'NF1

     

T192.1

NI

NI

Yes

202, IVS12, J1J2, IVS27

     

T197

NI

NI

Yes

J1J2

     

T227.2

NI

NI

Yes

IVS12, J1J2

     

T230.2

NI

NI

Yes

202, IVS12, IVS27

     

T232.2

NI

NI

Yes

J1J2

     

T241

NI

NI

Yes

J1J2

     

NF253_32

NI

NI

Yes

rs1018190, rs9891455,

rs8074061

NF1

Array CGH

Mitotic recombination

6/28

2

T224.1

NI

NI

 

LOH

 

NIA

  

Unpublished data, Cardiff

T162

NI

NI

 

LOH

     

T172

NI

NI

 

LOH

     

T179.1

NI

NI

 

LOH

     

T204.2

NI

NI

 

LOH

     

T224.2

NI

NI

 

LOH

     

T173.1

NI

NI

 

LOH

     

T179.2

NI

NI

 

LOH

     

T1281.2

NI

NI

 

LOH

     

T1281.4

NI

NI

 

LOH

     

T220

NI

NI

 

LOH

     

T221

NI

NI

 

LOH

     

T223

NI

NI

 

LOH

     

T258.1

NI

NI

 

LOH

     

T258.2

NI

NI

 

LOH

     

SCs from cutaneous neurofibromas

        

T543.2

Ex4a:

c.373delGinsATGTGT;

p.Arg125HisfsX4

Indel (FS)

Yes

J1J2-3'NF1

    

Unpublished data, Cardiff

T536A

Ex40: c.7127_7258del132

[Exon 40 deletion?]

132 bp deletion (FS)

Yes

J1J2-IVS38

 

NIA

  

Unpublished

data, Cardiff

T541.2

  

Yes

EV120-3'NF1

     

T541.4

  

Yes

EV120-3'NF1

     

T539

90 kb Deletion

Genomic deletion

   

Duplication:

Ex19b-25

  

Unpublished data, Cardiff

PNFs

         

37a

Ex24: c.4268A > G;

p.Lys1423Arg

Missense

Yes

HHH202, E5, I12b,

EVI20,3'NF1-1

Complete gene deletion

(1.4 Mb)

NF1

(1.4 Mb)

MLPA

Genomic deletion

20/29

10

37b

  

Yes

IVS27, EVI20, IVS38,

3'NF1-1 Probable gene

deletion

NF1 and 3' flanking

region

MLPA

Genomic deletion

20/29

10

T210.2

PNF

Ex42: c.7458delC;

p.Tyr2486IlefsX15

1 bp deletion (FS)

Yes

LOH detected in only 30% of cells

  

30% whole gene deletion

 

Unpublished data, Cardiff

T261

PNF

Ex3: c.288 + 1 delG

1 bp deletion at a splice site

LOH IVS38

      

605-1

Ex4a: c.289-2A > G

Splice site

Yes

D17S975, IVS27TG24.8,

IVS27TG28.4,

D17S1166, D17S1880,

D17S907, D17S1788,

D17S1861, D17S1809,

D17S668, D17S928

NF1 and flanking regions

MLPA

Mitotic recombination

13/43

11

47/T411

Ex4a:

c.440_441GC > AA;

p.Cys147X

Nonsense

LOH IVS27,

IVS38,

3'NF1-1

IVS38, 3'NF1-1

NF1 and 3' flanking

region

NIA

 

20/29

10

8/T328

Ex4b: c.480-2A > G

Splice site

LOH:

IVS27, IVS38

IVS27, IVS38

Intragenic NF1

MLPA

Mitotic recombination

20/29

10

335-3

Ex4b: c.528T > A;

p.Asp176Glu

Missense

Yes

D17S2237,

IVS27TG24.8,

D17S1166, D17S1800

NF1

MLPA

Genomic deletion

13/43

11

59

Ex6: c.752dupA;

p.Asp241GlufsX7

Small Insertion (fs)

Yes

intron 38 marker 53.0

Intragenic NF1

NIA

 

1/38

12

T265.2

Ex9: c.1186-13delT

(Pathogenicity?)

1 bp deletion within a splice site

LOH ivs27,

ivs38

      

374-4

Ex10a: c.1318C > T;

p.Arg440X

Nonsense

Yes

IVS27TG24.8,

IVS27TG28.4,

D17S1166, D17S1880,

D17S907, D17S1861

NF1 and 3' flanking region

MLPA

Mitotic

recombination

13/43

11

14a/

T412

Ex13: c.2076C > G;

p.Tyr692X

Nonsense

I12B, 3' NF1

I12B, 3' NF1-1

NF1 and 3' flanking region

MLPA

Mitotic recombination

20/29

10

T263

Ex15: c.2326-2A > T

Splice site

LOH ivs27

[rest hom]

      

22/T394

Ex16: c.2446C > T;

p.Arg816X

Nonsense

IVS27

IVS 27, EVI20

Intragenic NF1

MLPA

Mitotic recombination

20/29

10

T437.2

Ex16: c.2497delT;

p.Ser833ProfsX7

1 bp deletion (FS)

1-6ex

1,2,3,4a,4b,4c,

6 deletion

  

NIA

   

T212

Ex16: c.2705deT;

p.Met902ArgfsX22

1 bp deletion (FS)

    

Ex1-Ex 41

deletion

[variable ?]

  

18/T298

Ex18: c.3113 + 1G > A

Splice site

LOH

:HHH202,

IVS 27

IVS 27

Intragenic

NF1

MLPA

Inconclusive

20/29

10

30/T342

Ex19a: c.3123G > T;

p.Met1041Ile

Missense

Yes

Determined by MLPA

NF1

(1.4 Mb)

MLPA

Genomic

deletion

20/29

10

5

Ex20:

c.345&_3460delCTCA;

p.Leu1153MetfsX3

4 bp

deletion

(FS)

Yes

NF1 gene

NF1

  

1/3

13

23/

T373.2

Ex22: c.3826C > T;

p.Arg1276X

Nonsense

WG deletion

[mixed cell

population]

IVS 27, IVS38

Intragenic

NF1

MLPA

Inconclusive

20/29

10

452T

Ex23.2: c.4084C > T;

p.Arg1362X

Nonsense

Yes

NF-exon5 RFLP, NF-

(GATN)n intron 26, NF-

Alu(AAAT)n(i27b), NF-

EVI2B RFLP(i27b), NF-

EVI2A RFLP(i27b), NF-

IVSAC28.4(i27b), NF-

Evi-20, NF-

IVS38TG53.0, NF intron

41 RFLP, D17S57

(EW206), D17S250,

D17S1301, D17S384

NF1 and

3' flanking

region

NIA

 

4/10

9

27/T301

Ex23.2: c.4095C > A;

p.Cys1365X

Nonsense

Yes

Determined by MLPA

Intragenic

NF1

MLPA

Genomic

deletion

20/29

10

T330

Ex24: c.4267A > G;

p.Lys1423Glu

Missense

IVS27

  

NIA

   

6/T362/

T395

Ex24: c.4268A > G;

p.Lys1423Arg

Missense

Yes

EW206, EW207

Intragenic

NF1

MLPA

Inconclusive

20/29

 

T362

PNF

Ex24: c.4268A > G;

p.Lys1423Arg

Missense

LOH:

HHH202, E5,

I12b, EVI20,

3'NF

  

NIA

   

T395

PNF

Ex24: c.4268A > G;

p.Lys1423Arg

Missense

LOH:IVS27,

EVI20, IVS38,

3'NF1-1

      

317-1

Ex25: c.4270-2A > G

Splice site

Yes

IVS27TG24.8,

IVS27TG28.4,

D17S1166

NF1

MLPA

Genomic

deletion

13/43

11

T393

Ex27a: c.4537C > T;

p.Arg1513X

Nonsense

    

Whole gene

deletion

  

26/T300

Ex29:

c.5227_5229delGTAinsT;

p.Val1743TyrfsX17

Indel (FS)

Yes

Determined by MLPA

NF1

(1.4 Mb)

MLPA

Genomic

deletion

20/29

10

338-2

Ex29: c.5290delG;

p.Ala1764LeufsX8

1 bp

deletion

(FS)

Yes

D17S783, D17S975,

IVS27TG28.4,

D17S1166, D17S1880

NF1 and

flanking

regions

MLPA

Genomic

deletion

13/43

11

952-8

Ex30: c.5749 + 4delA

Splice site

Yes

D17S975, D17S1880,

D17S907, D17S1788,

D17S1861, D17S1809,

D17S668, D17S928

NF1 and

flanking

regions

MLPA

Genomic

deletion

  

34/T392

Ex31:

c.5750_5754dupGTATT;

p.Glu1919ValfsX4

5 bp

duplication

(FS)

Yes

EVI20, IVS38, 3'NF1-1,

NF1 and

3' flanking

region

NIA

 

20/29

10

21/T357

Ex37: c.6791dupA;

p.Tyr2264X

1 bp

duplication

(FS)

LOH: EW206

EW206

Intragenic

NF1

MLPA

Mitotic

recombination

  

T375

Ex40: c.7237C > T;

p.Gln2413X

Nonsense

16Ex 16

deletion,

ex13 & 18

also lower

  

NIA

   

7

Ex41: c.7285C > T;

p.Arg2429X

Nonsense

Yes

HHH202, IVS27

Intragenic

NF1

MLPA

Mitotic

recombination

  

15/T407

Ex46: c.7926dupT;

p.Lys2643X

1 bp

duplication

(FS)

LOH 3'NF1-1,

EW206

3'NF1-1

NF1 and

3' flanking

region

MLPA

Inconclusive

  

c1 UK/

T56

Ex46: c.8035A > T;

p.Thr2679Ser

Missense

LOH IVS27

IVS27

Intragenic

NF1

NIA

   

T408

Segmental NF1 NI

NI

LOH: IVS27,

IVS38,

3'NF1-1

      

T377

Segmental NF1 NI

NI

WG deletion

      

39

Segmental NF1 NI

NI

Yes

Determined by MLPA

NF1

(1.1 Mb)

MLPA

Genomic

deletion

  

43

Segmental NF1 NI

NI

Yes

IVS27, IVS38, 3'NF1-1

NF1 and

3' flanking

region

MLPA

Mitotic

recombination

  

T385.1

NI

NI

Yes

  

NIA

  

Unpublished

data, Cardiff

T385.2

NI

NI

LOH/del

      

T316

NI

NI

Yes

LOH:

HHH202,

E5, I12b,

EVI20,3'NF,

C71/2, EW206

     

76, 45-95

NI

NI

Yes

IVS27AC28.4,

IVS27TG24.8,

IVS38GT53

Intragenic

NF1

NIA

 

8/14

14

x1, 47-95

NI

NI

Yes

IVS27AC28.4, M98509,

IVS38GT53

Intragenic

NF1

    

x1, 27-97

NI

NI

Yes

IVS27AC28.4, M98509,

IVS38GT53

Intragenic

NF1

    

293,

71-97

NI

NI

Yes

M98509, IVS27TG24.8,

IVS38GT53

Intragenic

NF1

    

293,

124-98

NI

NI

Yes

M98509, IVS27TG24.8,

IVS38GT54

Intragenic

NF1

    

290,

83-97

NI

NI

Yes

IVS27AC28.4,

IVS27TG24.8,

IVS38GT53

Intragenic

NF1

    

290,

121-98

NI

NI

Yes

IVS27AC28.4,

IVS27TG24.8,

IVS38GT53

Intragenic

NF1

    

292,

122-98

NI

NI

Yes

IVS27TG24.8,

IVS38GT53

Intragenic

NF1

    

PD-T1

NI

NI

Yes

NF-Alu(AAAT)n(i27b),

D17S1800

Intragenic

NF1

NIA

 

4/10

9

386T

NI

NI

 

NF-Alu(AAAT)

n(i27b), NF-

IVSAC28.4(i27b),

NF-Evi-20, NF-

IVS38TG53.0,

D17S1800

NF1

    

454T-V

NI

NI

Yes

NF-Alu(AAAT)n(i27b),

NF-EVI2B RFLP(i27b),

NF-IVSAC28.4(i27b),

NF-Evi-20, NF intron 41

RFLP, D17S57

(EW206), D17S1301

NF1

    

NF284-1

NI

NI

Yes

Exon 28 14bp

duplication marker

(specific

to germline

lesion found)

Intragenic

NF1

  

1/1

8

2654-97

NI

NI

Yes

Determined by FISH

Whole

chromosome

FISH

Genomic

deletion

1/11

15

385

NI

NI

Yes

D17S975, D17S1880,

D17S907, D17S1788,

D17S1861, D17S1809,

D17S668, D17S928

NF1 and

flanking

regions

MLPA

Mitotic

recombination

13/43

11

389-2

NI

NI

Yes

D17S975, D17S1307,

D17S2237,

IVS27TG28.4,

D17S1800, D17S1880,

D17S907, D17S1861,

D17S1809, D17S668,

D17S928

NF1 and

flanking

regions

MLPA

Mitotic

recombination

  

604-4

NI

NI

Yes

D17S1800, D17S1880,

D17S907, D17S1861,

D17S928

NF1 and

flanking

regions

MLPA

Mitotic

recombination

  

913-5

NI

NI

Yes

D17S2237,

IVS27TG24.8,

D17S1880, D17S1788,

D17S1861

NF1 and

3' flanking

region

MLPA

Genomic

deletion

  

612-1

NI

NI

Yes

D17S1307, D17S2237,

IVS27TG24.8,

D17S1166, D17S1800,

D17S1880

NF1 and

flanking

regions

MLPA

Genomic

deletion

  

337-5

NI

NI

Yes

D17S1307, D17S2237,

IVS27TG24.8,

D17S1166, D17S1800

NF1

MLPA

Genomic

deletion

  

390

NI

NI

Yes

IVS27TG24.8,

IVS27TG28.4,

D17S1166, D17S1800

NF1

MLPA

Genomic

deletion

  

49

NI

NI

Yes

HHH202, E5, I12b,

EVI20, 3'NF1-1, C71/2,

EW206

NF1

MLPA

Inconclusive

20/29

10

Spinal neurofibromas

         

1

Ex7: c.899T > C;

p.Leu300Pro

Missense

Yes

EVI20, IVS38

Intragenic

NF1

MLPA

Mitotic

recombination

8/22

16

7

Ex9: c.1186-13delT

(Pathogenicity?)

1 bp

deletion

(FS)

Yes

IVS27, IVS38

Intragenic

NF1

MLPA

Mitotic

recombination

  

3

Ex16: c.2410-2A > T

Splice site

Yes

IVS27

Intragenic

NF1

MLPA

Mitotic

recombination

  

11.1

Ex22: c.3827G > A;

p.Arg1276Glu

Missense

Yes

IVS38

Intragenic

NF1

MLPA

Mitotic

recombination

  

11.2

  

Yes

Deletion of exons

13 > 16

Intragenic

NF1

MLPA

Deletion

  

2

Ex23.2: c.4066G > A;

p.Glu1356Lys

Missense

Yes

27, 3'NF1

NF1

MLPA

Mitotic

recombination

  

10

Ex29: c.5242C > T;

p.Arg1748X

Nonsense

Yes

I12B, Alu1, J1J2 and

EVI20

Intragenic

NF1

MLPA

Mitotic

recombination

  

MPNSTs

         

T196.20

Deletion exons 2 and 3

Two exon

deletion

Yes

I12b, IVS27AC28.4,

EVI20(IVS27B),

IVS38GT53.0 (IVS38),

3'-NF1, C7/CT1/2

(3'-UTR), EW206

(3extragenic), EW207

(3'extragenic), D17S798

NF1 and

3' flanking

region

MLPA

Mitotic

recombination

2/11

1

T196.24

  

Yes

NF1 exon 5, I12b,

IVS27AC28.4,

EVI20(IVS27B),

IVS38GT53.0 (IVS38),

3'-NF1, C7/CT1/2

(3'-UTR), EW206

(3'extragenic), EW207

(3'extragenic)

NF1 and

3' flanking

region

MLPA

Genomic

deletion

2/11

1

13

Deletion exons 2 and 3

Two exon

deletion

Yes

Ex5, I12b, IVS27, EVI20,

IVS38,C7CT, EW206,

EW207,3'NF1

NF1 and

3' flanking

region

MLPA/CGH

array

Genomic

deletion

31/34

17

7

Ex4c: c.654 + 1G > T

Splice site

Yes

UT172, HH202, J1/J2,

EVI20

NF1

MLPA/CGH

array

Genomic

deletion

  

27

Ex8:

c.1133_1136delACTG;

p.Asp378AlafsX7

4 bp

deletion

(FS)

Yes

Ex5, J1J2,3'NF1

NF1 and

3' flanking

region

NIA

   

9

Ex11: c.1713G > A;

p.Trp571X

Nonsense

Yes

D17S182, I12b, J1/J2

Intragenic

NF1

    

10

  

Yes

UT172, HH202, J1/J2,

EVI20, > 2.2Mb

NF1

MLPA/CGH

array

Genomic

deletion

  

23

Ex12a: c.1318C > T;

p.Arg440X

Nonsense

Yes

HHH202, EVI20. IVS38

Intragenic

NF1

NIA

   

14

Ex12a:

c.1754_1757delTAAC;

p.Thr586ValfsX19

4 bp

deletion

(FS)

Yes

IVS27, 3'NF1

NF1 and

3' flanking

region

MLPA/CGH

array

Mitotic

recombination

  

12

Ex13: c.2002-14C > G

Splice site

Yes

I12b, IVS27, EVI20,

IVS38, 3'NF

NF1 and

3' flanking

region

MLPA/CGH

array

Genomic

deletion

  

43

Ex13: c.2041C > T;

p.Arg681X

Nonsense

Yes

Determined by MLPA

NF1

MLPA

Duplication

mitotic

recombination

6/25

18

15

Ex16: c.2497delT;

p.Ser833ProfsX7

1 bp

deletion

(FS)

 

Intragenic Deletion

(Exons 1-6) MLPA

Intragenic

NF1

MLPA/CGH

array

Genomic

deletion

31/34

17

25

Ex16: c.2705delT;

p.Met902ArgfsX22

1 bp

deletion

(FS)

Yes

Intragenic deletion

(exons1-41) MLPA

Intragenic

NF1

MLPA/CGH

array

Genomic

deletion

  

17

Ex20:

c.3457_3460delCTCA;

p.Leu1153MetfsX3

4 bp

deletion

(FS)

   

NIA

   

18

  

Yes

3'NF1

Intragenic

NF1

MLPA/CGH

array

Genomic

deletion

  

459T1

Ex21: c.3684delC;

p.Asn1229MetfsX11

1 bp

deletion

(FS)

Yes

TP53(INTRON1),

TP53(INTRON6), NF-

(GATN)n INTRON26,

NF-IVSAC28.4(i27b),

D17S57, D17S250,

D17S1301, D17S784

Whole

chromosome

NIA

 

3/5

9

8

Ex22: c.3732delT;

p.Thr1245Leufsx21

1 bp

deletion

(FS)

Yes

Int12, J1J2

Intragenic

NF1

  

31/34

17

64

Ex23.1: c.3368 + 1delG

1 bp

deletion at

a splice site

Yes

Determined by MLPA

NF1

MLPA

Genomic

deletion

6/25

18

56

Ex25: c.4276C > A;

p.Gln1426Lys

Missense

Yes

Determined by MLPA

NF1

MLPA

Duplication

mitotic

recombination

  

4

Ex27a: c.4537C > T;

p.Arg1513X

Nonsense

Yes

IVS27b

Intragenic

NF1

MLPA/CGH

array

Genomic

deletion

31/34

17

6

Ex28: c.5003insTG;

p.Tyr1668LeufsX7

2 bp

insertion

(FS)

Yes

I4b, J1J2, EVI20

NF1

MLPA/CGH

array

Genomic

deletion

  

21

Ex29: c.5234C > G;

p.Ser1745X

Nonsense

Yes

Partial gene deletion

Intragenic

NF1

MLPA/CGH

array

Genomic

deletion

  

19

Ex37: c.6792C > A;

p.Tyr2264X

Nonsense

Yes

I12b, IVS27, J1J2, EVI20,

IVS38, C7CT

NF1

MLPA/CGH

array

Genomic

deletion

  

24

Ex38: c.6961insC;

p.Leu2321ProfsX5

1 bp

duplication

(FS)

Yes

Determined by MLPA

NF1

MLPA

Genomic

deletion

6/25

18

1

Ex41:

c.7268_7269delCA;

p.Thr2423SerfsX2

2 bp

deletion

(FS)

Yes

Intron 41-30

Intragenic

NF1

MLPA/CGH

array

Genomic

deletion

31/34

17

58

NI

NI

Yes

HHH202, NF1, EW206

Intragenic

NF1

 

Genomic

deletion

6/11

19

52

NI

NI

Yes

HHH202, NF1, EW206,

EW207

Intragenic

NF1

 

Genomic

deletion

  

22

NI

NI

Yes

HHH202

Intragenic

NF1

 

Genomic

deletion

  

8

NI

NI

Yes

EW206, EW207

Intragenic

NF1

 

Genomic

deletion

  

2

NI

NI

Yes

p144D6, pYNZ22.1,

pYNH37.3, EW503

NF1 region

and some

17p

 

Genomic

deletion

5/6

20

3

NI

NI

Yes

EW503, EW301 (B),

EW301 (T)

Intragenic

NF1

 

Genomic

deletion

  

4

NI

NI

Yes

p144D6, pYNZ22.1,

pYNH37.3, EW503,

EW301 (T), pHHH202,

EW207 (B), pTHH59

Whole

chromosome

 

Genomic

deletion

  

5

NI

NI

Yes

p144D6, pYNZ22.1,

pYNH37.3, EW503,

EW301 (B), EW301 (T),

pHHH202, EW207

(B)

Whole

chromosome

 

Genomic

deletion

  

10

NI

NI

Yes

p144D6, pYNZ22.1,

NF1 region

and some

17p

 

Genomic

deletion

  

88-3/14

NI

NI

Yes

D17S30, TP53, D17S71,

D17S8, D17S57

Whole

chromosome

G-banded

chromosome

17

duplication

Genomic

duplication

3/9

21

88-8

NI

NI

Yes

D17S30, D17S71

NF1

NIA

   

88-18

NI

NI

Yes

D17S30, D17S71,

D17S21, D17S33,

EVI2B, D17S82

Whole

chromosome

    

1

NI

NI

Yes

DI7S5, DI7SI, DI7SI37,

CRYBI, NF1, DI7S146

NF1 and

flanking

regions

NIA

 

2/5

22

4

NI

NI

Yes

DI7S34, DI7S5, DI7S146

NF1 and

flanking

regions

    

1

NI

NI

Yes

 

NF1

 

Genomic

deletion

1/1

23

1

NI

NI

Yes

NF1 alu, TP53 BHP53

Whole

chromosome

NIA

 

3/7

24

7

NI

NI

Yes

CRYB1, NF1 alu, TP53

BHP53

Whole

chromosome

    

8

NI

NI

Yes

D17S4, D17S74, NF1

e.31, NF1 alu

NF1

    

441T

NI

NI

Yes

TP53(INTRON6),

D17S1863,

D17twbch = S33, NF-

IVSAC28.4(i27b),

NF-Evi-20,

NF-IVS38TG53.0,

D17S1800, D17S73,

D17S1301

Whole

chromosome

NIA

 

3/5

9

396T4

NI

NI

Yes

NF-IVSAC28.4(i27b,

NF-IVS38TG53.0,

D17S57, D17S250,

D17S1301

NF1 and 3' flanking

region

    

2

NI

NI

Yes

NF1, P16, TP53

Whole

chromosome

NIA

 

5/8

13

5a

NI

NI

Yes

NF1, P16, TP53

Whole

chromosome

    

5b

NI

NI

Yes

NF1, P16, TP53

Whole

chromosome

    

6a

NI

NI

Yes

NF1, P16, TP53

Whole

chromosome

    

6b

NI

NI

Yes

NF1, P16, TP53

Whole

chromosome

    

2

NI

NI

Yes

Total gene deletion

NF1

MLPA/CGH

array

Genomic

deletion

31/34

17

5

NI

NI

Yes

Total gene deletion

NF1

MLPA/CGH

array

Genomic

deletion

  

24

NI

NI

Yes

EVI20, IVS27, IVS38

Intragenic

NF1

MLPA/CGH

array

Genomic

deletion

  

26

NI

NI

Yes

NF1 gene deletion

NF1

MLPA/CGH

array

Genomic

deletion

  

48

NI

NI

Yes

Determined by MLPA

NF1

MLPA

Genomic

deletion

6/25

18

86

NI

NI

Yes

Determined by MLPA

NF1

MLPA

Genomic

deletion

  

ACs

         

T65.1

Ex24: c.4267A > G;

p.Lys1423Glu

Missense

Yes

NS

NF1 3' flanking

region

NIA

 

1/1

25

57

NI

NI

Yes

EW206

Intragenic

NF1

NIA

 

1/1

19

58

NI

NI

Yes

D17S1849, D17S1863,

D17S1880

NF1 and 3'

flanking

region

NIA

 

2/4

26

76

NI

NI

Yes

D17S1863, D17S1880

NF1 and 3'

flanking

region

    

182

NI

NI

Yes

IVS27TG24.8

Intragenic

NF1

NIA

 

11/12

27

185

NI

NI

Yes

IVS27AC28.4,

IVS38GT53, D17S804

NF1 region

and some

17p

    

187

NI

NI

Yes

IVS27AC28.4,

IVS38GT53, D17S796

NF1 region

and some

17p

    

309

NI

NI

Yes

IVS38GT53, D17S796

NF1 region

and some

17p

    

330

NI

NI

Yes

IVS27AC28.4,

IVS38GT53, D17S520,

D17S796, D17S804

NF1 region

and some

17p

    

502

NI

NI

Yes

IVS27AC28.4, D17S520,

D17S796

NF1 region

and some

17p

    

519

NI

NI

Yes

IVS27TG28.4, M98509,

IVS27TG24.8,

IVS38GT53

Intragenic

NF1

    

297

NI

NI

Yes

IVS27TG28.4, M98509,

IVS38GT53

Intragenic

NF1

    

609

NI

NI

Yes

IVS27TG28.4, M98509

Intragenic

NF1

    

20954

NI

NI

Yes

IVS27TG24.8,

IVS38GT53

Intragenic

NF1

    

20962

NI

NI

Yes

IVS27AC28.4, M98509,

IVS38GT53

Intragenic

NF1

    

1

NI

NI

Yes

Homozygous

 

FISH

Unknown

3/4

28

9

NI

NI

Yes

Homozygous

 

FISH

Genomic

deletion

  

10

NI

NI

Yes

Homozygous

 

FISH

Genomic

deletion

  

Gastric carcinoid tumours

         

1

Ex37: c.6841C > T;

p.Gln2281X

Nonsense

Yes

IVS27TG24, D17S250

Intragenic

NF1

NIA

 

1/1

29

GISTs

         

1

Ex27a: c.4537C > T;

p.Arg1513X

Nonsense

Yes

D17S841, Alu, IVS27GT,

IVS27CAGT, IVS38,

3'NF1-1, 3'NF1-2

NF1 and 3'

flanking

region

MLPA

Mitotic

recombination

1/1

30

NF1-3

Ex45: c.7807delG;

p.Aal2603LeufsX3

1 bp

deletion

(FS)

Yes

Alu, IVS27AC33.1,

IVS38GT53.0,

IVS27TG24.8

Intragenic

NF1

Array CGH

Genomic

deletion

1/7

3

JMML

         

D102

Ex4b: c.574C > T;

p.Arg192X

Nonsense

Yes

D17S925, D17S1800,

D17S1880, D17S855,

D17S1827, D17S787,

D17S948, D17S784

Majority

of 17q

SNP array

Mitotic

recombination-

UPD

4/5

31

D115

Ex13: c.2066delT;

p.Val689GlyfsX59

1 bp

deletion

(FS)

Yes

D17S925, D17S1800,

D17S1880, D17S855,

D17S1827, D17S787,

D17S948, D17S784

Majority

of 17q

SNP array

Mitotic

recombination-

UPD

  

D003

Ex22: c.3861_3862delCT;

p.Cys1288ValfsX21

2 bp

deletion

(FS)

Yes

D17S925, D17S1800,

D17S1880, D17S855,

D17S1827, D17S787,

D17S948, D17S784

Majority

of 17q

SNP array

Mitotic

recombination-

UPD

  

D126

Ex44: c.7699C > T;

p.Gln2567X

Nonsense

Yes

D17S925, D17S1800,

D17S1880, D17S855,

D17S1827, D17S787,

D17S948, D17S784

Majority

of 17q

SNP array

Mitotic

recombination-

UPD

  

1

NI

NI

Yes

D17S1975, D17S1294,

UT172, NF1,

D17S1800, D17S250,

D17S801, D17S939,

D17S836, D17S1806,

D17S1822, D17S1830

Majority

of 17q

FISH

Mitotic

recombination-

interstitial

isodisomy

(paternal)

10/10

32

2

NI

NI

Yes

D17S1975, D17S1294,

UT172, NF1,

D17S1800, D17S250,

D17S801, D17S939,

D17S836, D17S1806,

D17S1822, D17S1830

Majority

of 17q

FISH

Mitotic

recombination-

interstitial

isodisomy

(paternal)

  

3

NI

NI

Yes

D17S1294, UT172,

NF1, D17S1800,

D17S250, D17S801,

D17S939, D17S836,

D17S1806, D17S1822,

D17S1830

Majority

of 17q

FISH

Mitotic

recombination

interstitial

isodisomy

(paternal)

  

4

NI

NI

Yes

D17S1975, D17S1294,

UT172, NF1,

D17S1800, D17S250,

D17S801, D17S939,

D17S836, D17S1806,

D17S1822, D17S1830

Majority

of 17q

FISH

Mitotic

recombination-

interstitial

isodisomy

(maternal)

  

5

NI

NI

Yes

D17S1975, D17S1294,

UT172, NF1,

D17S1800, D17S250,

D17S801, D17S939,

D17S836, D17S1806,

D17S1822

Majority of

17q

FISH

Mitotic

recombination-

interstitial

isodisomy

(maternal)

  

6

NI

NI

Yes

D17S1878, D17S33,

D17S1975, D17S1294,

UT172, NF1,

D17S1800, D17S250,

D17S801, D17S939,

D17S836, D17S1806,

D17S1822, D17S1830

Majority of

17q

FISH

Mitotic

recombination-

interstitial

isodisomy

(maternal)

  

7

NI

NI

Yes

D17S1294, UT172,

NF1, D17S1800,

D17S250, D17S801,

D17S939, D17S836,

D17S1806, D17S1822,

D17S1830, D17S928

Majority of

17q

FISH

Mitotic

recombination-

interstitial

isodisomy

(maternal)

  

8

NI

NI

Yes

D17S1975, D17S1294,

UT172, NF1,

D17S1800, D17S250,

D17S801, D17S939,

D17S836, D17S1806,

D17S1822, D17S1830,

D17S928

Majority of

17q

FISH

Mitotic

recombination-

interstitial

isodisomy

(paternal)

  

9

NI

NI

Yes

NF1, D17S1800

Intragenic

NF1

FISH

Genomic

deletion

  

10

NI

NI

Yes

NF1, D17S1800

Intragenic

NF1

FISH

Genomic

deletion

  

D419

NI

NI

Yes

D17S925, D17S1841,

D17S1294, D17S1863,

D17S1849, D17S1166,

D17S1800, D17S1880,

D17S1818, D17S855,

D17S1827, D17S787,

D17S948, D17S785,

D17S784

Majority of

17q

MLPA

Mitotic

recombination-

UPD

5/10

33

D561

NI

NI

Yes

D17S1294, D17S1863,

D17S1849, D17S1166,

D17S1800, D17S1880,

D17S1818, D17S855,

D17S1827, D17S787,

D17S948, D17S785,

D17S784

Majority of

17q

MLPA

Mitotic

recombination-

UPD

  

D378

NI

NI

Yes

D17S1294, D17S1863,

D17S1849, D17S1166,

D17S1800, D17S1880,

D17S1818, D17S855,

D17S785

Majority of

17q

Array CGH

Mitotic

recombination-

UPD

  

D341

NI

NI

Yes

D17S1849, D17S1166,

D17S1800, D17S1880

NF1 and

flanking

regions

Array CGH

Genomic

deletion

  

D566

NI

NI

Yes

D17S1849, D17S1166,

D17S1800, D17S784

NF1 and

flanking

regions

Array CGH

Genomic

deletion

  

PCs

         

1

NI

NI

Yes

DI7S34, DI7S137,

CRYBI, NF1, DI7S4

Whole

chromosome

NIA

 

7/7

22

2

NI

NI

Yes

CRYBI, DI7S33, NF1,

DI7S55, DI7S4

NF1

    

3

NI

NI

Yes

DI7S5, DI7S134,

DI7S58, DI7S33

Whole

chromosome

    

4

NI

NI

Yes

DI7S33, NF1

Intragenic

NF1

    

5

NI

NI

Yes

DI7S71, NF1, DI7S226

Whole

chromosome

    

6L

NI

NI

Yes

DI7S5, NF1, DI7S145,

DI7S226

Whole

chromosome

    

6R

NI

NI

Yes

DI7S5, NF1, DI7S145,

DI7S226

Whole

chromosome

    

1

NI

NI

Yes

TP53-BAM, TP53 AccII,

NF1-AE25 (BgIII) SNP,

THH59-TaqI,

THH59-PvuII

Majority of

17

NIA

 

2/7

34

1

NI

NI

Yes

NF1-AE25 (BgIII) SNP,

THH59-TaqI, THH59-

PvuII-adrenal corticoid

tumour

NF1 and 3'

flanking

region

    

NS

NI

NI

Yes

    

14/21

35

Glomus tumours

         

NF1-G2

Ex42: c.7395_7404del10;

p.Thr2466SerfsX33

10 bp

deletion

(FS)

Yes

Introns 27-38

Intragenic

NF1

Array CGH

Mitotic

recombination

1/7

36

CGH, comparative genomic hybridisation; array CGH, high resolution CGH; FS, frame shift; NI, not informative; WG, whole gene; NA, not available; UPD, uniparental disomy; MLPA, multiplex ligation-dependent probe amplification; FISH, fluorescent in situ hybridisation.

Supplementary Table References

1. Spurlock, G., Griffiths, S., Uff, J. and Upadhyaya, M. (2007), 'Somatic alterations of the NF1 gene in an NF1 individual with multiple benign tumours (internal and external) and malignant tumour types', Fam. Cancer Vol. 6, pp. 463-471.

2. De Raedt, T., Maertens, O., Chmara, M., Brems, H. et al. (2006), 'Somatic loss of wild type NF1 allele in neurofibromas: Comparison of NF1 microdeletion and non-microdeletion patients', Genes Chromosomes Cancer Vol. 45, pp. 893-904.

3. Maertens, O., Brems, H., Vandesompele, J., De Raedt, T. et al. (2006), 'Comprehensive NF1 screening on cultured Schwann cells from neurofi-bromas', Hum. Mutat. Vol. 27, pp. 1030-1040.

4. Thomas, L., Kluwe, L., Chuzhanova, N., Mautner, V. et al. (2010), 'Analysis of NF1 somatic mutations in cutaneous neurofibromas from patients with high tumor burden', Neurogenetics Vol. 11, pp. 391-400.

5. Serra, E., Puig, S., Otero, D., Gaona, A. et al. (1997), 'Confirmation of a double-hit model for the NF1 gene in benign neurofibromas', Am. J. Hum. Genet. Vol. 61, pp. 512-519.

6. Serra, E., Ars, E., Ravella, A., Sánchez, A. et al. (2001), 'Somatic NF1 mutational spectrum in benign neurofibromas: mRNA splice defects are common among point mutations', Hum. Genet. Vol. 108, pp. 416-429.

7. Serra, E., Rosenbaum, T., Nadal, M., Winner, U. et al. (2001), 'Mitotic recombination effects homozygosity for NF1 germline mutations in neu-rofibromas', Nat. Genet. Vol. 28, pp. 294-296.

8. Eisenbarth, I., Beyer, K., Krone, W. and Assum, G. (2000), 'Toward a survey of somatic mutation of the NF1 gene in benign neurofibromas of patients with neurofibromatosis type 1', Am. J. Hum. Genet. Vol. 66, pp. 393-401.

9. Rasmussen, S., Overman, J., Thomson, S., Colman, S. et al. (2000), 'Chromosome 17 loss-of-heterozygosity studies in benign and malignant tumors in neurofibromatosis type 1', Genes Chromosomes Cancer Vol. 28, pp. 425-431.

10. Upadhyaya, M., Spurlock, G., Monem, B., Thomas, N. et al. (2008), 'Germline and somatic NF1 gene mutations in plexiform neurofibromas', Hum. Mutat. Vol. 29, pp. E103-E111.

11. Steinmann, K., Kluwe, L., Friedrich, R., Mautner, V. et al. (2009), 'Mechanisms of loss of heterozygosity in neurofibromatosis type 1-associated plexiform neurofibromas', J. Invest. Dermatol. Vol. 129, pp. 615-621.

12. Däschner, K., Assum, G., Eisenbarth, I., Krone, W. et al. (1997), 'Clonal origin of tumor cells in a plexiform neurofibroma with LOH in NF1 intron 38 and in dermal neurofibromas without LOH of the NF1 gene', Biochem. Biophys. Res. Commun. Vol. 234, pp. 346-350.

13. Frahm, S., Mautner, V., Brems, H., Legius, E. et al. (2004), 'Genetic and phenotypic characterization of tumor cells derived from malignant peripheral nerve sheath tumors of neurofibromatosis type 1 patients', Neurobiol. Dis. Vol. 16, pp. 85-91.

14. Kluwe, L., Friedrich, R. and Mautner, V. (1999), 'Allelic loss of the NF1 gene in NF1-associated plexiform neurofibromas', Cancer Genet. Cytogenet. Vol. 113, pp. 65-69.

15. De Luca, A., Buccino, A., Gianni, D., Mangino, M. et al. (2003), 'NF1 gene analysis based on DHPLC', Hum. Mutat. Vol. 21, pp. 171-172.

16. Upadhyaya, M., Spurlock, G., Kluwe, L., Chuzhanova, N. et al. (2009), 'The spectrum of somatic and germline NF1 mutations in NF1 patients with spinal neurofibromas', Neurogenetics Vol. 10, pp. 251-263.

17. Upadhyaya, M., Kluwe, L., Spurlock, G., Monem, B. et al. (2008), 'Germline and somatic NF1 gene mutation spectrum in NF1-associated malignant peripheral nerve sheath tumors (MPNSTs)', Hum. Mutat. Vol. 29, pp. 74-82.

18. Bottillo, I., Ahlquist, T., Brekke, H., Danielsen, S. et al. (2009), 'Germline and somatic NF1 mutations in sporadic and NF1-associated malignant peripheral nerve sheath tumours', J. Pathol. Vol. 217, pp. 693-701.

19. Skuse, G., Kosciolek, B. and Rowley, P. (1989), 'Molecular genetic analysis of tumors in von Recklinghausen neurofibromatosis: Loss of het-erozygosity for chromosome 17', Genes Chromosomes Cancer Vol. 1, pp. 36-41.

20. Menon, A., Anderson, K., Riccardi, V., Chung, R. et al. (1990), 'Chromosome 17p deletions and p53 gene mutations associated with the formation of malignant neurofibrosarcomas in von Recklinghausen neu-rofibromatosis', Proc. Natl. Acad. Sci. USA Vol. 87, pp. 5435-5439.

21. Glover, T., Stein, C., Legius, E., Andersen, L. et al. (1991), 'Molecular and cytogenetic analysis of tumors in von Recklinghausen neurofibroma-tosis', Genes Chromosomes Cancer Vol. 3, pp. 62-70.

22. Xu, W., Mulligan, L.M., Ponder, M.A., Liu, L. et al. (1992), 'Loss of NF1 alleles in phaeochromocytomas from patients with type I neurofi-bromatosis', Genes Chromosomes Cancer Vol. 4, pp. 337-342.

23. Legius, E., Marchuk, D., Collins, F. and Glover, T. (1993), 'Somatic deletion of the neurofibromatosis type 1 gene in a neurofibrosarcoma supports a tumour suppressor gene hypothesis', Nat. Genet. Vol. 3, pp. 122-126.

24. Lothe, R., Slettan, A., Saeter, G., Brøgger, A. et al. (1995), 'Alterations at chromosome 17 loci in peripheral nerve sheath tumors', J. Neuropathol. Exp. Neurol. Vol. 54, pp. 65-73.

25. Upadhyaya, M., Han, S., Consoli, C., Majounie, E. et al. (2004), 'Characterization of the somatic mutational spectrum of the neurofibro-matosis type 1 (NF1) gene in neurofibromatosis patients with benign and malignant tumors', Hum. Mutat. Vol. 23, pp. 134-146.

26. Gutmann, D., Donahoe, J., Brown, T., James, C. et al. (2000), 'Loss of neurofibromatosis 1 (NF1) gene expression in NF1-associated pilocytic astrocytomas', Neuropathol. Appl. Neurobiol. Vol. 26, pp. 361-367.

27. Kluwe, L., Hagel, C., Tatagiba, M., Thomas, S. et al. (2001), 'Loss of NF1 alleles distinguish sporadic from NF1-associated pilocytic astrocyto-mas', J. Neuropathol. Exp. Neurol. Vol. 60, pp. 917-920.

28. Gutmann, D., James, C., Poyhonen, M., Louis, D. et al. (2003), 'Molecular analysis of astrocytomas presenting after age 10 in individuals with NF1', Neurology Vol. 61, pp. 1397-1400.

29. Stewart, W., Traynor, J.P., Cooke, A., Griffiths, S. et al. (2007), 'Gastric carcinoid: Germline and somatic mutation of the neurofibromatosis type 1 Gene', Fam. Cancer Vol. 6, pp. 147-152.

30. Stewart, D., Corless, C., Rubin, B., Heinrich, M. et al. (2007), 'Mitotic recombination as evidence of alternative pathogenesis of gastrointestinal stromal tumours in neurofibromatosis type 1', J. Med. Genet. Vol. 44, p. e61.

31. Flotho, C., Steinemann, D., Mullighan, C., Neale, G. et al. (2007), 'Genome-wide single-nucleotide polymorphism analysis in juvenile mye-lomonocytic leukemia identifies uniparental disomy surrounding the NF1 locus in cases associated with neurofibromatosis but not in cases with mutant RAS or PTPN11', Oncogene Vol. 26, pp. 5816-5821.

32. Stephens, K., Weaver, M., Leppig, K., Maruyama, K. et al. (2006), 'Interstitial uniparental isodisomy at clustered breakpoint intervals is a frequent mechanism of NF1 inactivation in myeloid malignancies', Blood Vol. 108, pp. 1684-1689.

33. Steinemann, D., Arning, L., Praulich, I., Stuhrmann, M. et al. (2010), 'Mitotic recombination and compound-heterozygous mutations are predominant NF1-inactivating mechanisms in children with juvenile myelomonocytic leukemia and neurofibromatosis type 1', Haematologica Vol. 95, pp. 320-323.

34. Gutmann, D.H., Cole, J.L., Stone, W.J., Ponder, B.A. et al. (1994), 'Loss of neurofibromin in adrenal gland tumors from patients with neurofibro-matosis type I', Genes Chromosomes Cancer Vol. 10, pp. 55-58.

35. Bausch, B., Borozdin, W., Mautner, V.F., Hoffmann, M.M. et al. (2007), 'Germline NF1 mutational spectra and loss-of-heterozygosity analyses in patients with pheochromocytoma and neurofibromatosis type 1', J. Clin. Endocrinol. Metab. Vol. 92, pp. 2784-2792.

36. Brems, H., Park, C., Maertens, O., Pemov, A. et al. (2009), 'Glomus tumors in neurofibromatosis type 1: Genetic, functional, and clinical evidence of a novel association', Cancer Res. Vol. 69, pp. 7393-7401.

37. Wiest, V., Eisenbarth, I., Schmegner, C., Krone, W. et al. (2003), 'Somatic NF1 mutation spectra in a family with neurofibromatosis type 1: Toward a theory of genetic modifiers', Hum. Mutat. Vol. 22, pp. 423-427.

38. Sawada, S., Florell, S., Purandare, S., Ota, M. et al. (1996), 'Identification of NF1 mutations in both alleles of a dermal neurofibroma', Nat. Genet. Vol. 14, pp. 110-112.

39. John, A., Ruggieri, M., Ferner, R. and Upadhyaya, M. (2000), 'A search for evidence of somatic mutations in the NF1 gene', J. Med. Genet. Vol. 37, pp. 44-49.

Table 1

Contribution of LOH and NF1 micro-lesions to the somatic NF1 mutational spectrum in different types of NF1-associated tumour

Tumour type

LOH

Point mutations

Total

Dermal neurofibroma

144 (40%)

211 (60%)

355

Plexiform neurofibroma

67 (79%)

18 (21%)

85

Spinal neurofibroma

7 (70%)

3 (30%)

10

MPNST

55 (85%)

10 (15%)

65

Astrocytoma

18 (100%)

0 (0%)

18

GIST/gastric carcinoid

3 (38%)

5 (62%)

8

JMML

18 (95%)

1* (5%)

19

Phaeochromocytoma

10 (100%)

0 (0%)

10

Glomus tumour

1 (14%)

6 (86%)

7

Overall

323 (55%)

254 (44%)

577

* Compound heterozygous NF1 mutations were identified in five of six haemopoietic tumours analysed. As no other normal tissues were available in these five cases, it was not possible to distinguish between the associated germline and somatic NF1 mutations.

Table 2

Mechanistic basis of the NF1 gene-associated LOH identified in different NF1-associated tumours

Tumour type

Tumour showing mitotic recombination (number & percentile)

Tumours with genomic deletions (number & percentile)

Dermal neurofibroma

28 (76%)

8 (24%)

Plexiform neurofibroma

11 (44%)

14 (56%)

Spinal neurofibroma

7 (88%)

1 (12%)

MPNST

5 (16%)

26 (84%)

Astrocytoma

0 (0%)

2 (100%)

GIST/gastric carcinoid

1 (50%)

1 (50%)

JMML

15 (79%)

4 (21%)

Phaeochromocytoma

0 (0%)

0 (0%)

Glomus tumour

1 (100%)

0 (0%)

Tabulated information only given for tumours in which the precise LOH mechanism was identifiable.

Tumour DNA analysis has also identified 254 somatic NF1 gene lesions, including nonsense, missense, splice site, microdeletion/microinsertions ( < 20 bp), indels (combined insertion-deletion events) and larger ( > 20 bp) deletions/insertions (Tables 3). The consequences of all deletions and insertions for the reading frame were also determined, with five sequence changes being compound heterozygous NF1 mutations found in five haemopoietic tumours; however, with no other tissue available for analysis, it was not possible to differentiate between germline and somatic NF1 point mutations (Table S2 (Table 5)). About 75 per cent (191/254) of the somatic mutations associated with NF1 tumours comprise mutations that are predicted to give rise to truncated proteins. Of these 191 changes, only 18 result from the insertion or duplication of bases; the remaining 173 truncations arise from deletion, nonsense mutation or frameshift events. Splice site mutations form a considerable proportion (39/254; 15.0 per cent) of the mutational spectrum, while missense changes only account for some 9.4 per cent (24/254) of the somatic NF1 mutations.
Table 3

The spectrum and percentile distribution of somatic NF1 micro-lesions reported in different NF1-associated tumours

Tumour type

Mutation type

 

Deletion

Insertion

Indel

Nonsense

Splice site

Missense

Truncating

Total

Dermal neurofibroma

82 (39%)

15 (7%)

2 (1%)

59 (28%)

32 (15%)

21 (10%)

158 (75%)

211

Plexiform neurofibroma

6 (33%)

1 (6%)

-

7 (39%)

2 (11%)

2 (11%)

14 (78%)

18

Spinal neurofibroma

-

-

-

-

2 (66%)

1 (33%)

0

3

MPNST

7 (70%)

1 (10%)

1 (10%)

1 (10%)

-

-

10 (100%)

10

GIST/gastric carcinoid

1 (20%)

-

-

3 (60%)

1 (20%)

-

4 (80%)

5

JMML*

*

*

*

1 (100%)

*

*

1 (100%)

1

Glomus tumour

2 (33%)

1 (17%)

-

1 (17%)

2 (33%)

-

4 (67%)

6

Overall

98 (39%)

18 (7%)

3 (1%)

72 (28%)

39 (15%)

24 (9%)

191 (75%)

254

* Compound heterozygosity of NF1 mutations in several JMML tumours cases meant it was not possible to distinguish between associated germline and somatic NF1 mutations.

Table S2

Summary of germline and somatic point mutations in NF1-associated tumours

Patient ID

Germline point mutation

Type of germline mutation

Somatic point mutation

Effect of somatic mutation

Source

Dermal neurofibromas

T196.3

Ex 2 and 3 deleted

2 exon deletion

Ex4c: c.648dup73 p.Leu216

(through splice site)

73 bp

duplication

(FS)

1

T196.12

  

Ex4c: c.655-1G > A

Splice site

 

T196.15

  

Ex6: c.750delT

p.Phe250LeufsX30

1 bp deletion

(FS)

 

T196.16

  

Ex16: c.2534_2557del24

p.Cys845X

24 bp deletion

(In-frame)

 

T196.7

  

Ex16: c.2844delA

p.Gly949AspfX3

1 bp deletion

(FS)

 

T196.4

  

Ex18: c.3047_c3048delGT

p.Cys1016SerfsX4

2 bp deletion

(FS)

 

T196.5

  

Ex27a: c.4537C > T

p.Arg1513X R

Nonsense

 

T196.13

  

Ex27b: c.4743delG

p.Asp1582IlefsX21

1 bp deletion

(FS)

 

T196.1

  

Ex44: c.7721_7722delAA

p.Lys257Ser4fsX4

2 bp deletion

(FS)

 

T543.1

Ex4a: c.373delGinsATGTGT

p.Arg125HisfsX22

Indel (FS)

Ex21: c.3568del80

p.Gly1190HisfsX3

80 bp deletion

(FS)

Unpublished data,

Cardiff

T543.3

  

Ex26: c.4388C > T

p.Ser1463Phe

Missense

 

T128.10

Ex6: c.784C > T p.Arg262Cys

Missense

Ex4b: c.574C > T p.Arg192X

R

Nonsense

Unpublished data,

Cardiff

T128.1

  

Ex8: c.1170delC

p.Asp390LysfsX6

1 bp deletion

(FS)

 

T128.17

  

Ex10c: c.1556A > C

p.Gln519Pro R

Missense

 

T128.8

  

Ex32: c.6055_6056delTC

p.Ser2019TrpfsX18

2 bp deletion

(FS)

 

NF29a-4

Ex6: c.801G > A p.Trp267X

Nonsense

Ex10a: c.1381C > T

p.Arg461X

Nonsense

37

NF17-8

  

Ex10c: c.1528-14_1546del33

p.Asp510fs (through splice

site)

32 bp deletion

[FS]

 

NF17-1

  

Ex10c: c.1641 + 1G > A

Splice site

 

NF17-9

  

Ex18: c.3049C > T

p.Glu1017X

Nonsense

 

NF29a-7

  

Ex19b: c.3303_3314+7del19

p.Glu1101 (through splice site)

19 bp deletion

[FS]

 

NF17-15

  

Ex23.1: c.3916C > T

p.Arg1306X R

Nonsense

 

NF29a-9

  

Ex27b: c.4756insT

p.Tyr1586LeufsX14

1 bp insertion

(FS)

 

NF17-18

  

Ex28: c.5205 + 1G > A

Splice site

 

NF17-23

  

Ex31: c.5772_5775delTTTG

p.Cys1924TrpfsX4

4 bp deletion

(FS)

 

NF29a-5

  

Ex40: c.7237_7253del17

p.Gln2413fsX2

17 bp deletion

(FS)

 

L-002 F

Ex9: c.1246C > T p.Arg416X

Nonsense

Ex3: c.246_247delTC

p.Glu83SerfsX15

2 bp deletion

(FS)

3

L-002 A

  

Ex5: c.655-1G > T

Splice site

 

L-002 D

  

Ex8: c.1105C > T p.Gln369X

Nonsense

 

L-002 E

  

Ex8: c.1153delC

p.Arg385AlafsX2

1 bp deletion

(FS)

 

L-002 B

  

Ex22: c.3757_3764del8

p.Leu1253ThrfsX8

8 bp deletion

(FS)

 

NF282-1

Ex9: c.1260+1G > A

Splice site

Ex23.2: c.4021C > T

p.Gln1341X

Nonsense

8

NF282-2

  

Ex23.2: c.4084C > T

p.Arg1362X

Nonsense

 

T473.6

Ex10b: c.1413_1414delAG

p.Lys471AsnfsX1

2 bp deletion

(FS)

Ex7: c.890delA

p.Leu297SerfsX20

1 bp deletion

(FS)

4

T473.12

  

Ex12b: c.1884insA p.Tyr628X

1 bp insertion

(FS)

 

T473.11

  

Ex16: c.2451insG

p.Ser818ValfsX12

1 bp insertion

(FS)

 

T473.18

  

Ex22: c.3807insC

p.Ser1270LeufsX13

1 bp insertion

(FS)

 

T473.20

  

Ex23.2: c.4087delA

p.Ser1363ValfsX22

1 bp deletion

(FS)

 

T473.13

  

Ex31: c.5888A > C

p.Asn1963Thr

Missense

 

T473.33

  

Ex34: c.6478A > G

p.Ser2160Gly

Missense

 

T473.36

  

Ex38: c.6859delG

p.Asp2287ThrfsX18

1 bp deletion

(FS)

 

T473.17

  

Ex40: c.7128delG

p.Tyr2377ThrfsX23

1 bp deletion

(FS)

 

T82.3

Ex12a: c.1754_1757delTAAC

p.Thr585ValfsX18

4 bp deletion

(FS)

Ex16: c.2445delG

p.Arg815SerfsX5

1 bp deletion

(FS)

Unpublished data,

Cardiff

T82.5

  

Ex35: c.6621_6625delGTGGA

p.Gln2207HisfsX11

5 bp deletion

(FS)

 

T77.3

Ex12a: c.1783G > A

p.Glu595Lys

Missense

Ex16: c.2446C > T

p.Arg816X R

Nonsense

Unpublished data,

Cardiff

T77.1

  

Ex29: c.5242C > T

p.Arg1748X R

Nonsense

 

T77.4

  

Ex31: c.5839C > T

p.Arg1947X

Nonsense

 

T141.4

Ex13: c.2233delA

p.Ser745AlafsX2

1 bp deletion

(FS)

Ex12b: c.1885G > A

p.Gly629Arg

Missense

Unpublished data,

Cardiff

T141.13

  

Ex30: c.5731delT

p.Ser1911LeufsX9 R

2 bp deletion

(FS)

 

T133

Ex16: c.2446C > T

p.Arg816X

Nonsense

Ex31: c.5897dupAC

p.Glu1966HisfsX25

2 bp

duplication

(FS)

Unpublished data,

Cardiff

T137

  

Ex31: c.5898dupAC

p.Glu1966HisfsX25

2 bp

duplication

(FS)

 

T437

Ex17: c.2875C > T

p.Gln959X

Nonsense

Ex2: c.67A > T p.Ile23Leu

Missense

4

T441

  

Ex4b: c.586G > T p.Glu196X

Nonsense

 

T459

  

Ex10c: c.1641+2T > G

Splice site

 

T433

  

Ex10c: c.1660C > G

p.Gln554Glu

Missense

 

T469

  

Ex12a: c.1724delCACA

p.Ser575X

4 bp deletion

(FS)

 

T468

  

Ex13: c.2041C > T p.Arg681X

Nonsense

 

T472

  

Ex13: c.2088G > A p.Trp696X

Nonsense

 

T463

  

Ex16: c.2410-3T > G

Splice site

 

T451

  

Ex20: c.3449C > T

p.Ser1150Leu

Missense

 

T456

  

Ex22: c.3709-2A > G

Splice site

 

T450

  

Ex23.2: c.4084C > T

p.Arg1362X R

Nonsense

 

T442

  

Ex27b: c.4687_4691del5

p.Phe1563GlyfsX36

5 bp deletion

(FS)

 

T443

  

Ex27b: c.4693insG

p.Ala1565GlyfsX35

1 bp insertion

(FS)

 

T467

  

Ex29: c.5380C > T

p.Gln1794X

Nonsense

 

T457

  

Ex34: c.6448A > T

p.Lys2150X

Nonsense

 

T471

  

Ex38: c.6895delG

p.Val2299TrpfsX8

1 bp deletion

(FS)

 

T434

  

Ex44: c.7699C > T

p.Gln2567X

Nonsense

 

T435

  

Ex44: c.7702C > T

p.Gln2568X

Nonsense

 

T460

  

Ex46: c.7924delT

p.Ser2642LeufsX16

1 bp deletion

(FS)

 

CSG6N

Ex21: c.3525_3526delAA

p.Arg1176SerfsX18

2 bp deletion

(FS)

Ex4c: c.587-8del6 Splicing

effect?

Intronic

deletion

6, 7

CSG13N

  

Ex9: c.1260 + 1G > A

Splice site

 

CSG48N

  

Ex10c: c.1604A > G

p.Gln535Arg

Missense

 

CSG29N

  

Ex14: c.2266C > T p.Gln756X

Nonsense

 

CSG33N

  

Ex16: c.2816delA

p.Asn939IlefsX12

1 bp deletion

(FS)

 

CSG19N

  

Ex17: c.2928del13

p.Glu977AsnfsX3

13 bp deletion

(FS)

 

CSG26N

  

Ex26: c.4514 + 1G > C

Splice site

 

CSG44N

  

Ex31: c.5774delT

p.Leu1925TrpfsX4

1 bp deletion

(FS)

 

CSG8N

  

Ex33: c.6292_6322del31

p.Arg2098PhefsX21

31 bp deletion

(FS)

 

CSG30N

  

Ex45: c.7908-2A > T

Splice site

 

NF482-

UHG B

Ex21: c.3525_3526delAA

p.Arg1176SerfsX18

2 bp deletion

(FS)

Ex4a: c.359_375del17

p.Phe120X

17 bp deletion

(FS)

3

NF482-

UHG C

  

Ex4c: c.603_621del19

p.Phe201fsX4

19 bp deletion

(FS)

 

NF482-

UHG A

  

Ex8: c.1185 + 1G > A

Splice site

 

NF482-

UHG D

  

Ex14: c.2252-30_2252-

6del??insT

Indel (FS?)

 

T191.5

Ex22: c.3721C > T

p.Arg1241X

Nonsense

Ex4b: c.505_524del20

p.Glu169X

20 bp deletion

(FS)

Unpublished data,

Cardiff

T191.9

  

Ex10b: c.1417delA

p.Thr473GlnfsX24

1 bp deletion

(FS)

 

T191.1

  

Ex18: c.2991 + 1 G > A

Splice site

 

T191.2

  

Ex22: c.3721C > T

p.Arg1241X R

Nonsense

 

T175.1

Ex23.2: c.4084C > T

p.Arg1362X

Nonsense

Ex12a: c.1738insT

p.Tyr580LeufsX7 R

1 bp insertion

(FS)

Unpublished data,

Cardiff

T175.2

  

Ex31: c.5817C > A

p.Cys1939X R

Nonsense

 

T209.1ii

Ex28: c.4950C > A

p.Tyr1650X

Nonsense

Ex7: c.1062 + 1G > A R

Splice site

Unpublished data,

Cardiff

T209.7

  

Ex10a: c.1318C > T

p.Arg440X R

Nonsense

 

T209.8

  

Ex15: c. 2326G > A

p. Ala776Thr R

Missense?/

splicing?

 

T209.5

  

Ex25: c.4345delA

p.Ser1449AlafsX12

1 bp deletion

(FS)

 

T209.6

  

Ex37: c.6790_6806del17

p.Tyr2264AspfsX8

17 bp deletion

(FS)

 

T506.5

Ex36: c.6756 + 2T > G

Splice site

Ex4b: c.480delG

p.Arg160SerfsX5

1 bp deletion

(FS)

4

T506.2

  

Ex6: c.731_732delAA

p.Glu244ValfsX5

2 bp deletion

(FS)

 

T506.4

  

Ex17: c.2987insAC

p.Val996AspfsX17

2 bp insertion

(FS)

 

T506.8

  

Ex19b: c.3306insA

p.Phe1103IlefsX2

1 bp insertion

(FS)

 

T506.1

  

Ex22: c.3745_3764del20

p.Ser1249ThrfsX7

20 bp deletion

(FS)

 

T506.9

  

Ex33: c.6364del114

p.Glu2122 (through splice site)

114 bp

deletion (FS)

 

T506.6

  

Ex40: c.7127-3T > G

Splice site

 

T106.3

Ex37: c.6791insA p.Tyr2264Xfs

1 bp insertion

(FS)

Ex13: c.2033delC

p.Pro678GlnfsX9 R

1 bp deletion

(FS)

Unpublished data,

Cardiff

T106.4

  

Ex26: c.4374_4375delCC

p.Leu1459X R

2 bp deletion

(FS)

 

T175.1

Ex37: c.6792C > G

p.Tyr2264X

Recurrent

nonsense

mutation that

causes a

splicing defect

Ex12a: c.1738insT

p.Tyr580LeufsX7 R

1 bp insertion

(FS)

Unpublished data,

Cardiff

T143.2

  

Ex19a: c.3124delGTAGinsAT

p.Val1042IlefsX16

Indel (FS)

 

T143.13

  

Ex30: c.5731delT

p.Ser1911LeufsX9 R

1 bp deletion

(FS)

 

T175.2A

  

Ex31: c.5817C > A

p.Cys1939X R

Nonsense

 

T541.3

Ex40: c.7127_7258del132

p.Gly2376. Is this a complete

exon 40 deletion??

132 bp Inframe deletion

(FS) Complete

exon 40

deletion ??

Ex12b: c.1888delG

p.Val630X R

1 bp deletion

(FS)

Unpublished data,

Cardiff

T541.1

  

Ex27b: c.4743insG

p.Asp1582GlufsX18

1 bp insertion

(FS)

 

T536B

  

Ex40: c.7169delG

p.Arg2390LysfsX6

1 bp deletion

(FS)

 

T210.1

Ex42: c.7458delC

p.Tyr2487Ilefs

1 bp deletion

(FS)

Ex7: c.1062 + 1G > A R

Splice site

Unpublished data, Cardiff

T210.6

  

Ex22: c.3870 + 2T > A

Splice site

 

T181.3

E6-27b: Partial deletion of

gene 90 kb

Partial gene

deletion

Ex3: c.227insG

p.Glu76GlyfsX30

1 bp insertion

(FS)

Unpublished data,

Cardiff

T211.2

  

Ex7: c.910C > T

p.Arg304X R

Nonsense

 

T211.3

  

Ex17: c 2855T > A

p.Leu952X

Nonsense

 

T34.1

  

Ex23.2: c 4108C > T

p.Gln1370X

Nonsense

 

T150.2

  

Ex34: c.6410delT

p.Leu2137TyrfsX40

1 bp deletion

(FS)

 

T181.1

  

Ex34: c.6409_6410delTT

p.Leu2137ThrfsX19

2 bp deletion

(FS)

 

T198

  

Ex42: c.7449delT

p.Ala2484GlnfsX18

1 bp deletion

(FS)

 

C176_3

NF1 microdeletion

Genomic

deletion

Ex4a: c.479 + 1G > A

Splice site

2

C174

  

Ex15: c.2326- ?_2409

Complete exon 15 deletion ?

Exon

deletion?

 

C186

  

Ex17: c.2990 + 1G > A R

Splice site

 

C176_1

  

Ex28: c.4812C > G

p.Tyr1604X R

Nonsense

 

C176_2

  

Ex31: c.5927G > A

p.Trp1976X R

Nonsense

 

L-001 D

NF1 microdeletion

Genomic

deletion

Ex4a: c.396_403del8

p.Leu134PhefsX21

8 bp deletion

(FS)

3

L-001 B

  

Ex19a: c.3189T > A

p.Cys1063X

Nonsense

 

L-001 E

  

Ex22: c.3774G > A

p.Trp1258X

Nonsense

 

L-001 C

  

Ex23.2: c.4086_4092del7

p.Arg1362AlafsX20

7 bp deletion

(FS)

 

L-001 A

  

Ex28: c.5026_5032del7

p.Leu1676Alafs10

17 bp deletion

(FS)

 

NF96-1 E

NF1 microdeletion

Genomic

deletion

Ex13: c.2050C > T

p.Glu684X

Nonsense

3

NF96-1 B

  

Ex20: c.3330delT

p.Phe1110LeufsX2

1 bp deletion

(FS)

 

NF96-1 A

  

Ex41: c.7394 + 1G > A

Splice site

 

NF96-1 C

  

Ex42: c.7438delG

p.Glu2480LysfsX22

1 bp deletion

(FS)

 

NF339-

UHG B

NF1 microdeletion

 

Ex3: c.288 + 2T > G

Splice site

3

NF339-

UHG C

  

Ex7: c.1007G > A

p.Trp336X

Nonsense

 

NF339-

UHG D

  

Ex15: c.2409 + 1G > A

Splice site

 

NF339-

UHG A

  

Ex27b: c.4697T > A

p.Leu1566X

Nonsense

 

T49.2

Ex1-42: gene deletion

E1-42: gene

deletion

Ex8: c.1177C > G

p.His393Asp

Missense

Unpublished data,

Cardiff

T49.8

  

Ex8: c.1178A > T

p.His393Leu

Missense

 

T49.1

  

Ex8: c.1181_1182delTT

p.Phe394X

2 bp deletion

(FS)

 

T49.5

  

Ex16: c.2446C > T

p.Arg816X R

Nonsense

 

T49.7

  

Ex17: c.2953C > T

p.Gln985X

Nonsense

 

T49.3

  

Ex24: c.4114_4115delGT

p.Val1372X

2 bp deletion

(FS)

 

T51.3

Whole gene deletion

Genomic

deletion

Ex7: c.1062 + 1G > A R

Splice site

Unpublished data,

Cardiff

T51.6

  

Ex8: c.1179_1180delCT

p.Phe394LeufsX18

2 bp deletion

(FS)

 

T51.5

  

Ex11: c.1645_1646delCT

p.Leu549AlafsX1

2 bp deletion

(FS)

 

T51.4

  

Ex16: c.2464G > T

p.Gly822X

Nonsense

 

T51.7

  

Ex41: c.7285C > T

p.Arg2429X R

Nonsense

 

T176.3

Large deletion

Genomic

deletion

Ex23.2: c.4110 + 1G > C

Splice site

Unpublished data,

Cardiff

T176.1

  

Ex28: c.4812C > G

p.Tyr1604X R

Nonsense

 

T176.2

  

Ex31: c.5928G > A

p.Trp1976X R

Nonsense

 

T217

Ex1: c.61-1G > C

Splice site

Ex12b: c.1900_1907del8

p.Ile634X

8 bp deletion

(FS)

Unpublished data,

Cardiff

T1440

Ex3: c.264_267delTACA

p.Thr89Trpfs

4 bp deletion

(FS)

Ex3: c.271G > A p.Glu91Lys

Missense

Unpublished data,

Cardiff

T183.1

Ex4a: c.373delGinsATGTGT

p.Arg125fs

Indel (FS)

Ex42: c.7449_7458del10

p.Leu2483IlefsX15

10 bp deletion (FS)

Unpublished data, Cardiff

T139

Ex4a: c.434_435delTC

p.Leu145GlufsX19

2 bp deletion

(FS)

Ex27a: c.4637C > G

p.Ser1546X

Nonsense

Unpublished data,

Cardiff

T108.12

Ex7: c.889-2A > G

Splice site

Ex7: c.910C > T p.Arg304X R

Nonsense

25

T199.1

Ex7: c.983_984delGT

p.Cys328Xfs

2 bp deletion

(FS)

Ex4b: c.528T > A

p.Asp176Glu

Missense

Unpublished data,

Cardiff

T374.5

Ex10a: c.1318C > T

p.Arg440X

Nonsense

Ex23.1: c.3916C > T

p.Arg1306X R

Nonsense

Unpublished data,

Cardiff

T996

Ex10b: c.1393-32T > C

Splice site

Ex6: c.731-11 T > G

Splice site

Unpublished data,

Cardiff

T227.3

Ex10b: c.1423insC

p.Leu475ProfsX9

1 bp insertion

(FS)

Ex15: c.2326-12C > T

Splice site

Unpublished data,

Cardiff

T161.4

Ex10b: c.1466A > G

p.Tyr489Cys

Missense

Ex17: c.2990 + 1G > A R

Splice site

Unpublished data,

Cardiff

T161.3

Ex10b: c.1466A > G

p.Tyr489Cys

Missense

Ex22: c.3721insC

p.Arg1241ProfsX7

1 bp insertion

(FS)

Unpublished data,

Cardiff

T214

Ex10b complete exon deletion

Single exon

deletion

Ex22: c.3826C > T

p.Arg1276X

Nonsense

Unpublished data,

Cardiff

CLJ8N

Ex13: c.2041C > T p.Arg681X

Nonsense

Ex13: c.2246C > G p.Ser749X

Nonsense

6, 7

T170.1A

Ex13: c.2041C > T p.Arg681X

Nonsense

Ex12a: c.1797G > A

p.Trp599X

Nonsense

Unpublished data, Cardiff

T1243

Ex13: c.2197_2214del17

p.Pro733fs

17 bp deletion

(FS)

Ex36: c.6709C > T

p.Arg2237X

Nonsense

Unpublished data,

Cardiff

NF253-

UHG D

Ex16: c.2850 + 2A > G

Splice site

Ex11: c.1663_1666delTTAG

p.Leu555IlefsX12

4 bp deletion

(FS)

3

T193

Ex17: c.2870delA

p.Asp957Ilefs

1 bp deletion

(FS)

Ex10a: c.1312G > T

p.Glu438X

Nonsense

Unpublished data,

Cardiff

L-004 D

Ex18: c.3113G > A

p.Arg1038Lys

Missense

Ex27b: c.4729delA

p.Thr1577LeufsX23

1 bp deletion

(FS)

3

HT1359.2

Ex18: c.3113 + 1G > A

Splice site

Ex10a: c.1277G > A

p.Trp426X R

Nonsense

Unpublished data,

Cardiff

T140.4

Ex22: c.3732delT

p.Thr1245LeufsX21

1 bp deletion

(FS)

Ex41: c.7285C > T

p.Arg2429X R

Nonsense

25

T37.1

Ex23.2: c.4084C > T

p.Arg1362X

Nonsense

Ex10b: c.1467T > G

p.Tyr489X

Nonsense

Unpublished data,

Cardiff

T205.1

Ex24: c.4196C > A

p.Ser1399X

Nonsense

Ex27a: c.4537C > T

p.Arg1513X R

Nonsense

Unpublished data,

Cardiff

T450.3

Ex27a: c.4537C > T

p.Arg1513X

Nonsense

Ex4b: c.574C > T

p.Arg192X R

Nonsense

Unpublished data,

Cardiff

T209.8

Ex:28: c.4950 C > G

p.Tyr1650X

Nonsense

Ex10a: c.1318 C > T

p.Arg440X R

Nonsense

Unpublished data,

Cardiff

NF116-

UHG A

Ex28: c.5122insG

p.Ala1708GlyfsX27

1 bp insertion

(FS)

Ex27a: c.4537C > T

p.Arg1513X R

Nonsense

3

T1308

Ex29: c.5546 + 19 T > A

Splice site

Ex22: c.3827G > A

p.Arg1276Gln

Missense

Unpublished data,

Cardiff

T149.5C

Ex34:

c.6512delATGAGAGAinsC

p.Tyr2171fs

Indel (FS)

Ex7: c.988G > A

p.Ala330Thr

Missense

Unpublished data,

Cardiff

T89.1

Ex37: c.6789_6792delTTAC

p.Asp2264ThrfsX5

4 bp deletion

(FS)

Ex12b: c.1888delG

p.Val630X R

1 bp deletion

(FS)

25

T106.1

Ex37: c.6791insA

p.Tyr2264XfsX1

1 bp insertion

(FS)

Ex13: c.2033delC

p.Pro678GlnfsX9 R

1 bp deletion

(FS)

25

L-004 B

Ex37: c.6791insA

p.Tyr2264XfsX1

1 bp insertion

(FS)

Ex23.1: c.3871_3974del103

Complete exon 23.1 deletion ?

103 bp

deletion (FS)

3

T1200

Ex37: c.6791insA

p.Tyr2264XfsX1

1 bp insertion

(FS)

Ex16: c.2825G > T

p.Ser942Ile

Missense

Unpublished data,

Cardiff

CLO1N

Ex37: c.6792C > A

p.Tyr2264X

Nonsense

mRNA study: Exon 4c skipped

Splice site?

6, 7

T1229

Ex39: c.7049_7064del16

p.Cys2350PhefsX19

16 bp deletion

(FS)

Ex13: c.2203T > C

p.Tyr735His

Missense

Unpublished data,

Cardiff

T164.1E

Ex41: c.7285C > T

p.Arg2429X

Nonsense

Ex23.2: c.4084C > T

p.Arg1362X R

Nonsense

Unpublished data,

Cardiff

T157.1A

Ex45: c.7907 + 3A > T

Splice site

Ex20: c.3492delC

p.Ile1165SerfsX2

1 bp deletion

(FS)

Unpublished data,

Cardiff

T98.6

1.5 Mb deletion

Genomic

deletion

Ex34: c.6387A > C

p.Arg2129Ser

Missense

25

T98

Complete gene deletion

Genomic

deletion

Ex20: c.3457_3460del4

p.Leu1153MetfsX3

4 bp deletion

(FS)

Unpublished data,

Cardiff

T158.1

Complete gene deletion

Genomic

deletion

Ex18: c.3058delG

p.Glu1020LysfsX2 R

1 bp deletion

(FS)

Unpublished data,

Cardiff

CCF1N

Complete gene deletion

Genomic

deletion

mRNA study: exons 12a and

12b skipped

Splice site?

5, 6

UWA128-

3

NI

NI

Ex4b: c.543_546delGTAT

p.Tyr182SerfsX7

4 bp deletion

(FS)

38

T219.1

NI

NI

Ex9: c.1225_1226delGT

p.Val409AlafsX18

2 bp deletion

(FS)

Unpublished data,

Cardiff

T116

NI

NI

Ex10c: c.1541_1542delAG

p.Gln514ArgfsX43

2 bp deletion

(FS)

25

T198.1

NI

NI

Ex10c: c.1555C > T

p.Gln519X

Nonsense

Unpublished data,

Cardiff

T128.17

NI

NI

Ex10c: c.1556A > C

p.Gln519Pro R

Missense

25

T198.2

NI

NI

Ex12a: c.1792A > T

p.Lys598X

Nonsense

Unpublished data,

Cardiff

T63.2

NI

NI

Ex13: c.2088delG p.Trp696X

1 bp deletion

(FS)

25

T146.5

NI

NI

Ex15: c.2326G > A

p.Ala776Thr R

Missense/

splicing?

Unpublished data,

Cardiff

T63.8

NI

NI

Ex15: c.2341_2358del18

p.His781Ala (in-frame)

18 bp deletion

(in-frame)

25

T1265.2

NI

NI

Ex17: c.2851-16T > C

Splice site

Unpublished data,

Cardiff

T233.1

NI

NI

Ex17: c.2879del38 p.Phe960X

38 bp deletion

(FS)

 

T158.2

NI

NI

Ex18: c.3058delG

p.Glu1020LysfsX2 R

1 bp deletion

(FS)

 

T158.4

NI

NI

Ex18: c.3058delG

p.Glu1020LysfsX2 R

1 bp deletion

(FS)

 

T192.1

NI

NI

Ex18: c.3113 + 1G > A R

Splice site

 

T192.2

NI

NI

Ex18: c.3113 + 1G > A R

Splice site

 

NF260-1

NI

NI

Ex22: c.3721C > T

p.Arg1241X R

Nonsense

8

38

NI

NI

Ex22: c.3727_3728delCT

p.Leu1243GlyfsX5

2 bp deletion

(FS)

18

T94

NI

NI

Ex23.2: c.4083insT

p.Arg1362SerfsX12

1 bp insertion

(FS)

25

T565

NI

NI

Ex25: c. 4270-2A > G

Splice site

Unpublished data,

Cardiff

T106.3

NI

NI

Ex26: c.4374_4375delCC

p.Asp1460X R

2 bp deletion

(FS)

25

T81.1

NI

NI

Ex27b: c.4662-5C > T

Splice site

25

T1284.5

NI

NI

Ex27b: c.4772 + 5G > A

Splice site

Unpublished data,

Cardiff

20

NI

NI

Ex33: c.6253_6354 + 5del117

p.Val2085 (through splice site)

17 bp deletion

(FS)

18

44

NI

NI

Ex40: c.7127-44_7174del92

p.Gly2376ValfsX8

92 bp deletion

(FS)

18

PNFs

45

Ex3: c.264_267delTACA

p.Thr89TrpfsX8

4 bp deletion

(FS)

Ex3: c.271G > A p.Glu91Lys

Missense

10

T399

Ex3: c.264_267delTACA

p.Thr89TrpfsX8

4 bp deletion

(FS)

Ex3: c.271G > T p.Glu91X

Nonsense

Unpublished data,

Cardiff

T7

Ex4a: c.479 + 1G > A

Splice site

Ex16: c.2446C > T

p.Arg816X R

Nonsense

39

19 UK

Ex7: c.910C > T p.Arg304X

Nonsense

Ex8: c.1177_1178delCA

p.His393LeufsX16

2 bp deletion

(FS)

Unpublished data,

Cardiff

c3 UK

Ex8: c.1063-2A > G

Splice site

Ex7: c.910C > T p.Arg304X R

Nonsense

 

14b

Ex13: c.2076C > G p.Tyr692X

Nonsense

Ex4b: c.532_558del27

p.Glu178 R

27 bp deletion

(in-frame)

 

T318

Ex13: c.2076C > G p.Tyr692X

Nonsense

Ex4b: c.532_558del27

p.Glu178 R

27 bp deletion

(in-frame)

 

T381.1

E18: c.3113 + 1G > A

Splice site

Ex10a: c.1277G > A

p.Trp426X R

Nonsense

 

T381.2

  

Ex18: c.3113 + 1G > A R

Splice site

 

31

Ex29: c.5234C > G

p.Ser1745X

Nonsense

Ex9: c.1246C > T p.Arg416X

Nonsense

 

c4 UK

Ex33: c.6289_6290insA

p.Leu2097fsX2

1 bp insertion

(FS)

Ex27b: c.4706T > G

p.Leu1569X R

Nonsense

 

T155

Ex33: c.6291insA

p.Leu2097XfsX9

1 bp insertion

(FS)

Ex27b: c.4706T > G

p.Leu1569X R

Nonsense

 

24

Complete gene deletion

Genomic

deletion

Ex4b: c.528T > A

p.Asp176Glu

Missense

Unpublished data,

Cardiff

T323

Complete gene deletion

(1.4 Mb ?)

Genomic

deletion

Ex26: c.4501_4502delCT

p.Leu1501PhefsX7 R

2 bp deletion

(FS)

 

T369

Complete gene deletion

(1.4 Mb ?)

Genomic

deletion

Ex26: c.4501_4502delCT

p.Leu1501PhefsX7 R

2 bp deletion

(FS)

 

c2 UK

NI

NI

Ex23.2: c.4083insT

p.Arg1362SerfsX12

1 bp insertion

(FS)

Unpublished data,

Cardiff

42

NI

NI

Ex27a: c.4515-2A > G

Splice site

 

T329 ?

NI

NI

Ex7: c.952_953delGA

p.Glu318LysfsX11

2 bp deletion

(FS)

 

Spinal neurofibromas

1

Ex7: c.899T > C p.Leu300Pro

Missense

Ex24: c.4111-2A > G

Splice site

16

13

1.4 Mb deletion

Genomic

deletion

Ex21_22 splice site mutation?

Splice site?

 

6

1.4 Mb deletion

Genomic

deletion

Ex27b: c.4690A > G

p.Lys1564Glu

Missense

 

MPNSTs

53

Ex4b: c.574C > T p.Arg192X

Nonsense

Ex24: c.4203insT p.Glu1402X

1 bp insertion

(FS)

18

T168

Ex5: c.663G > A p.Trp221X

Nonsense

Ex34: c.6444delA

p.Val2149SerfsX28

1 bp deletion

(FS)

 

T185

Ex6: c.773delA

p.Ser259AlafsX21

1 bp deletion

(FS)

Ex34: c.6410delT

p.Leu2137TyrfsX41

1 bp deletion (FS)

 

37

Ex16: c.2446C > T p.Arg816X

Nonsense

Ex6: c.731-5_741del19

through a splice site

19 bp deletion

(FS)

 

17

Ex20: c.3457_3460delCTCA

p.Leu1153MetfsX4

2 bp deletion

(FS)

Ex31: c.5789delC

p.Pro1930HisfX6

1 bp deletion

(FS)

17

20

1.4 Mb deletion

Genomic

deletion

Ex10c: c.1532delC

p.Pro511GlnfsX14

1 bp deletion

(FS)

17

44

Complete gene deletion

Genomic

deletion

Ex16: c.2446C > T

p.Arg816X R

Nonsense

18

T184

Segmental NF NI

NI

Ex27a: c.4580_4590del11

p.Pro1527GlnfsX11 R

11 bp deletion

(FS)

18

11

NI

NI

Ex27a: c.4580_4590del11

p.Pro1527GlnfsX11 R

11 bp deletion

(FS)

17

38

NI

NI

Ex12a: c.1831delCinsTT

p.Leu611PhefsX3

Indel (FS)

18

GISTs

NF1-1a

Ex24: c.4269 + 1G > T

Splice site

Ex29: c.5546 + 2T > A

Splice site

3

NF1-1b

  

Ex29: c.5242C > T

p.Arg1748X R

Nonsense

 

NF1-2a

Ex37: c.6791insA p.Tyr2264X

1 bp insertion

(FS)

Ex3: c.279T > A

p.Cys93X

Nonsense

3

NF1-2c

  

Ex10c: c. del21

21 bp in-frame

deletion

 

NF1-2b

  

Ex45: c.7846C > T

p.Arg2616X

Nonsense

 

JMML

D127

Ex14:

c.2288_2295dupTGAGGCGC

/Ex20: c.3366delT

Compound

heterozygous

NF1mutations

found in

blood cells

Ex14:

c.2288_2295dupTGAGGCGC

/Ex20: c.3366delT

Compound

heterozygous

NF1mutations

found in

blood cells

31

CZ051

Ex12a: c.1748A > G

p.Lys583Arg/Ex13:

c.2027delC p.T676TfsX11

 

Ex12a: c.1748A > G

p.Lys583Arg/Ex13:

c.2027delC p.T676TfsX11

  

D530

Ex6: c.821T > G p.Leu274Arg

/Ex34: c.6579 + 1G > C

With no

other tissue

analysed,

unable to

differentiate

germline from

somatic

NF1mutations

Ex6: c.821T > G p.L274R/

Ex34: c.6579 + 1G > C

With no

other tissue

analysed,

unable to

differentiate

germline from

somatic

NF1mutations

32

SC049

Ex3: c.205-2A > G/Ex23.2:

c.4084C > T p.Arg1362X

 

Ex3: c.205-2A > G/Ex23.2:

c.4084C > T p.R1362X

  

SCO87

Ex4b: c.482T > G p.Leu161X

/Ex4b: c.495_498delTGTT

p.T165TfsX11

 

Ex4b: c.482T > G p.L161X/

Ex4b: c.495_498delTGTT

p.T165TfsX11

  

D252

NI

NI

Ex29: c.5242C > T

p.Arg1748X R

Nonsense

 

Glomus tumours

NF1-G8

Ex4a: c.311T > G p.Leu104X

Nonsense

Ex44: c.7727C > A

p.Ser2576X

Nonsense

36

NF1-G3

Ex16: c.2546insG

p.Val850SerfsX15

1 bp insertion

(FS)

Ex29: c.5539_5546dup8

p.Ser1850ValfsX15

8 bp

duplication

(FS)

 

NF1-G5

Ex27a: c.4515-2A > T

Splice site

Ex18: c.3113 + 1G > C

Splice site

 

NF1-G1

mRNA study: Exon 29

partially skipped

Splice site?

Ex4a: c.403delC

p.Arg135GlyfsX30

1 bp deletion

(FS)

 

NF1-

G10a

Ex37: c.6789_6792delTTAC

p.Tyr2264AspfsX5

4 bp deletion

(FS)

Ex2: c.204 + 1G > A

Splice site

 

NF1-

G10b

  

Ex43: c.7600_7621del22

p.Lys2534GlyfsX8

22 bp deletion

(FS)

 

ACs

 

No NF1 somatic mutations

identified

 

No NF1 somatic mutations

identified

  

Gastric carcinoid tumours

 

No NF1 somatic mutations

identified

 

No NF1 somatic mutations

identified

  

PCs

 

No NF1 somatic mutations

identified

 

No NF1 somatic mutations

identified

  

FS, frame shift; NI, no information; R, recurrent.

Any attempt to make direct comparisons between the various tumour types would be unwise at this stage, owing to the paucity of somatic mutation data, especially for the less commonly encountered tumours. Table 3 nevertheless attempts to summarise the available data. The bias inherent in the data is immediately evident, with 211/254 (83 per cent) mutational changes originating from the analysis of cutaneous neurofibroma DNA. Hence, the relative frequencies of the various mutation types in cutaneous neurofibromas are essentially comparable with the germline mutational spectrum, with nonsense mutations, splice site mutations and missense alterations found in cutaneous neurofibromas at frequencies of 28 per cent (59/211), 15 per cent (32/ 211) and 10 per cent (21/211), respectively (Table 3). Table 3 does, however, serve to highlight the high proportion of truncating mutations (191/ 254; ~75 per cent) involved in the somatic inactivation of the NF1 gene in all tumour types, especially cutaneous neurofibromas.

An additional comparison between the frequency distributions of somatic microlesions and LOH is made in Table 1. There appears to be a marked difference between cutaneous neurofibromas, PNFs and MPNSTs, with 40 per cent, 79 per cent and 85 per cent, respectively, of somatic mutation events represented by LOH. This may be explained in part by the extent of the molecular rearrangements in each tumour type; MPNSTs, for example, would be predicted to exhibit a greater extent of genetic aberration than a benign dermal neurofibroma. The types of analyses performed, however, will have a direct influence on such conclusions, in that either microlesions or LOH may not be screened for in some studies.

In summary, the more severe MPNSTs show a greater degree of genetic abnormality than other tumour types, with LOH constituting a much more frequent event in these tumours. Further comparison within and between the rarer tumour types would not be valid, however, owing to the relative paucity of mutation data currently available for analysis.

Mutational mechanisms underlying the known somatic NF1gene lesions

Somatic inactivation of the NF1 gene may result from different mutational mechanisms and may involve intragenic mutations, LOH and epigenetic modification of the promoter region. Among the 254 somatic NF1 mutations listed in Table S2 (Table 5), 72 nonsense mutations were found, of which 36 involved mutations in just 15 codons in different tumours (codons 192, 304, 426, 440, 816, 1241, 1306, 1362, 1513, 1569, 1604, 1748, 1939, 1976 and 2429), with many previously reported in different tumours or different studies. Ten of these 15 different recurrent nonsense mutations involve C > T or G > A transitions within CpG dinucleotides and are compatible with the endogenous mutational mechanism of methylation-mediated deamination of 5-methylcytosine (5mC). Of these 72 nonsense mutations, 28 have also been reported as germline mutations in NF1 patients (Human Gene Mutation Database [HGMD]),[81] indicating that the same mutational mechanism is operating in both the soma and germline. The importance of this mutational mechanism is evidenced by the finding that 12 of the 15 recurrent somatic nonsense mutations have also been reported independently in the germline (codons 192, 304, 426, 440, 816, 1241, 1306, 1362, 1513, 1569, 1748 and 2429). For the ten of these 15 nonsense mutations that correspond to C > T or G > A transitions within CpG dinucleotides, we may infer that the mutated cytosine must be methylated both in the soma and in the germline, thereby explaining the vulnerability of these sites to methylation-mediated deamination in both cell lineages.

Among the somatic NF1 mutations listed in Table S2 (Table 5) are 21 different missense mutations. Of these, two (in codons 519 and 776) have been reported more than once in different tumours or different studies, although neither is compatible with methylation-mediated deamination of 5mC. Of the 21 missense mutations, only one (in codon 176) has also been reported in the germline (see HGMD). Since this Asp176Glu mutation has also been reported more than once in NF1-associated tumours, it may well be that this residue is of importance for the function of neurofibromin in both the soma and the germline. Furthermore, this residue is conserved in different species, including Drosophila and Fugu, and has not been identified in 250 unrelated normal individuals.

Nonsense mutations are not the only type of NF1 mutation to occur recurrently in the soma. Among the somatic NF1 microdeletions listed in Table S2 (Table 5) are five that have been reported more than once in different tumours (c.1888delG, c.2033delC, c.3058delG, c.4374_4375delCC and c.5731delT) with three microdeletions occurring in mononucleotide tracts (G4, C7 and T3, respectively), suggestive of a model of slipped mispairing at the DNA replication fork. Importantly, c.2033delC has also been reported in the germline (see HGMD), indicating that this tetranucleotide stretch is a hotspot for mutation in both the germline and the soma. A microinsertion (c.1733insT, located within a T6 tract) has also been found to occur recurrently in the soma but this has not so far been reported in the germline. The reader interested in a detailed comparative analysis of germline and somatic mutations in human TSGs is referred to Ivanov et al[82].

NF1gene somatic mutations in non-NF1-associated tumours

Various studies have identified somatic NF1 gene mutations in non-NF1-associated cancers. Thus, somatic NF1 aberrations have been identified in glioblastoma multiforme (GBM) tumours, lung adenocarcinomas, malignant breast tumours, leukaemia, ovarian serous carcinomas (OSCs) and neuroblastoma [1012, 1416, 83]. Some of the NF1 gene changes are relatively frequent in these tumours and therefore have the potential to represent specific prognostic and diagnostic markers. For example, 23 per cent of sporadic GBM tumours harbour an inactivating NF1 somatic mutation, and this may enable such GBM tumours to differentiate into the mesenchymal molecular subclass [13]. Similarly, in 22 per cent (9/41) of primary OSCs, an NF1 mutation was detected, six of which exhibited biallelic inactivation [12]. Interestingly, all nine of these OSC samples also contained a TP53 mutation, highlighting the likely involvement of this TSG in OSC pathogenesis [12].

Given the pivotal role that neurofibromin plays in several cell signalling pathways, it is not surprising that its loss will affect distinct molecular subtypes in different cancers. Indeed, the efficacy of any future therapeutic intervention for many tumours will almost certainly hinge upon our ability successfully to identify such molecular subclasses of tumour.

Prospects for the development of new treatments/therapies

As the complex picture underlying the molecular nature of NF1 tumorigenesis becomes better defined, the treatment regimens available to patients should greatly improve. Although the future is encouraging, the optimal treatment for NF1 tumours currently rests with their surgical resection, in spite of the high chance of recurrent malignancy. Gottfried and colleagues [84] have suggested that the recruitment of supporting cells around the neurofibroma, coupled with aberrant Remak bundles, could explain how the neurofibroma integrates into the surrounding tissue, and it is this that may lead to the surgical difficulties that often lead to tumour recurrence. Moreover, it has been suggested that surgical interference may even increase the recruitment of surrounding cell types, thereby inadvertently increasing the growth of lesions leading to the formation of new neurofibromas [84]. Surgical biopsy is therefore inherently problematic, and novel therapeutics are urgently required. Clinical and preclinical trials targeting different components of the Ras/MAPK signalling pathway and related growth factor receptors appear to be more promising. It is likely, however, that treatment with multiple drugs may be more effective for NF1 tumours [5].

Concluding remarks

Biallelic inactivation of the NF1 gene, resulting in the complete loss of functional neurofibromin, initiates the pathogenic process that eventually results in the formation of nerve sheath tumours. NF1 gene inactivation may occur through relatively subtle lesions that affect just a few DNA bases, or may involve large genomic changes that affect large chromosomal regions, or even the entire chromosome 17. This review demonstrates that NF1-associated tumour types display a considerable degree of variation in terms of the level of LOH detected, with cutaneous neurofibromas, PNFs and MPNSTs. MPNSTs manifest increased levels of deletion-based LOH, whereas cutaneous neurofibromas appear to be associated with a localised deletion of the NF1 gene through mitotic recombination (the situation in PNFs being somewhat intermediate). In MPNSTs, additional mutations at different gene loci are almost certainly involved in the progression of the tumour.

In terms of the molecular mechanisms of mutagenesis, both methylation-mediated deamination of 5-methylcytosine and slipped mispairing within polynucleotide tracts appear to be responsible for the occurrence of mutation hotspots in both the germline and the soma. For some types of tumour, there is interplay between the soma and the germline, in that the location of the germline mutation can influence the nature, frequency and location of the subsequent somatic mutation [85, 86]. As yet, however, there is no evidence for this phenomenon in the context of NF1 tumorigenesis.

Although our knowledge of the role of the NF1 gene in tumorigenesis is ever expanding, definitive markers of malignant transformation remain to be discovered. Mouse and other animal models, including zebrafish,[87] have provided new perspectives for research, with various knockout and mutagenesis studies potentiating functional studies. It is already clear that, in order to clarify the role of the NF1 gene in NF1-associated tumours, we must improve our understanding of the significance of the somatic (second-hit) mutations. The brief assessment of the compilation of somatic NF1 mutations in NF1-associated tumour types reported here failed to unearth any specific genotypic correlations. The limited size of the mutation dataset means that reliable conclusions are hard to draw, and that larger and better-defined patient groups will be needed, to allow more reliable comparisons to be made. Additionally, definitive prognostic markers should be identified that permit differentiation between benign neurofibromas that are likely to progress to malignancy and those that are not.

This review nevertheless emphasises that NF1 is a highly individual condition that exhibits extreme somatic mutational heterogeneity both within and between patients. These are the mutations which are ultimately responsible for the molecular changes that can lead to tumour formation. If we can come to understand how these changes bring about tumorigenesis, we shall be better placed not only with respect to the provision of genetic counselling, but also in terms of exploring new avenues for the development of new drug-based therapies.

Declarations

Acknowledgements

We are grateful to all our NF1 patients and their families for their support. We also thank Laura Thomas and Gill Spurlock for their help with the compilation of mutation data.

Authors’ Affiliations

(1)
Institute of Medical Genetics, School of Medicine, Cardiff University

References

  1. Huson S, Harper P, Compston D: Von Recklinghausen neurofibromatosis. A clinical and population study in south-east Wales. Brain. 1988, 111: 1355-1381. 10.1093/brain/111.6.1355.View ArticlePubMedGoogle Scholar
  2. Lammert M, Friedman JM, Kluwe L, Mautner VF: Prevalence of neurofibromatosis 1 in German children at elementary school enrollment. Arch Dermatol. 2005, 141: 71-74. 10.1001/archderm.141.1.71.View ArticlePubMedGoogle Scholar
  3. Upadhyaya M, Huson S, Davies M, Thomas N, et al: An absence of cutaneous neurofibromas associated with a 3-bp inframe deletion in exon 17 of the NF1 gene (c.2970-2972 delAAT): Evidence of a clinically significant NF1 genotype-phenotype correlation. Am J Hum Genet. 2007, 80: 140-151. 10.1086/510781.PubMed CentralView ArticlePubMedGoogle Scholar
  4. Upadhyaya M: Genetic basis of tumorigenesis in NF1 malignant peripheral nerve sheath tumors. Front Biosci. 2011, 16: 937-951. 10.2741/3727.View ArticleGoogle Scholar
  5. Upadhyaya M: Neurofibromatosis type 1 (NF1): Diagnosis and recent advances. Expert Opin Med Genet. 2010, 4: 307-322. 10.1517/17530059.2010.494660.View ArticleGoogle Scholar
  6. Knudson AJ: Mutation and cancer: Statistical study of retino-blastoma. Proc Natl Acad Sci USA. 1971, 68: 820-823. 10.1073/pnas.68.4.820.PubMed CentralView ArticlePubMedGoogle Scholar
  7. Pao W, Girard N: New driver mutations in non-small-cell lung cancer. Lancet Oncol. 2011, 12: 175-180. 10.1016/S1470-2045(10)70087-5.View ArticlePubMedGoogle Scholar
  8. Sawada S, Florell S, Purandare S, Ota M, et al: Identification of NF1 mutations in both alleles of a dermal neurofibroma. Nat Genet. 1996, 14: 110-112. 10.1038/ng0996-110.View ArticlePubMedGoogle Scholar
  9. Serra E, Puig S, Otero D, Gaona A, et al: Confirmation of a double-hit model for the NF1 gene in benign neurofibromas. Am J Hum Genet. 1997, 61: 512-519. 10.1086/515504.PubMed CentralView ArticlePubMedGoogle Scholar
  10. Parsons DW, Jones S, Zhang X, Lin JC, et al: An integrated genomic analysis of human glioblastoma multiforme. Science. 2008, 321: 1807-1812. 10.1126/science.1164382.PubMed CentralView ArticlePubMedGoogle Scholar
  11. Ding L, Getz G, Wheeler D, Mardis E, et al: Somatic mutations affect key pathways in lung adenocarcinoma. Nature. 2008, 455: 1069-1075. 10.1038/nature07423.PubMed CentralView ArticlePubMedGoogle Scholar
  12. Sangha N, Wu R, Kuick R, Powers S, et al: Neurofibromin 1 (NF1) defects are common in human ovarian serous carcinomas and co-occur with TP53 mutations. Neoplasia. 2008, 10: 1362-1372.PubMed CentralView ArticlePubMedGoogle Scholar
  13. Brennan C, Momota H, Hambardzumyan D, Ozawa T, et al: Glioblastoma subclasses can be defined by activity among signal transduction pathways and associated genomic alterations. PLoS One. 2009, 4: e7752-10.1371/journal.pone.0007752.PubMed CentralView ArticlePubMedGoogle Scholar
  14. McGillicuddy LT, Fromm JA, Hollstein PE, Kubek S, et al: Proteasomal and genetic inactivation of the NF1 tumor suppressor in gliomagenesis. Cancer Cell. 2009, 16: 44-54. 10.1016/j.ccr.2009.05.009.PubMed CentralView ArticlePubMedGoogle Scholar
  15. Haferlach C, Dicker F, Kohlmann A, Schindela S, et al: AML with CBFB-MYH11 rearrangement demonstrate RAS pathway alterations in 92% of all cases including a high frequency of NF1 deletions. Leukemia. 2010, 24: 1065-1069. 10.1038/leu.2010.22.View ArticlePubMedGoogle Scholar
  16. Hölzel M, Huang S, Koster J, Ora I, et al: NF1 is a tumor suppressor in neuroblastoma that determines retinoic acid response and disease outcome. Cell. 2010, 142: 218-229. 10.1016/j.cell.2010.06.004.PubMed CentralView ArticlePubMedGoogle Scholar
  17. Easton DF, Ponder MA, Huson SM, Ponder BA: An analysis of variation in expression of neurofibromatosis (NF) type 1 (NF1): Evidence for modifying genes. Am J Hum Genet. 2008, 53: 305-313.Google Scholar
  18. Kehrer-Sawatzki H, Cooper DN: Mosaicism in sporadic neurofibromatosis type 1: Variations on a theme common to other hereditary cancer syndromes?. J Med Genet. 2008, 45: 622-631. 10.1136/jmg.2008.059329.View ArticlePubMedGoogle Scholar
  19. Ballester R, Marchuk D, Boguski M, Saulino A, et al: The NF1 locus encodes a protein functionally related to mammalian GAP and yeast IRA proteins. Cell. 1990, 63: 851-859. 10.1016/0092-8674(90)90151-4.View ArticlePubMedGoogle Scholar
  20. Upadhyaya M, Kluwe L, Spurlock G, Monem B, et al: Germline and somatic NF1 gene mutation spectrum in NF1-associated malignant peripheral nerve sheath tumors (MPNSTs). Hum Mutat. 2008, 29: 74-82. 10.1002/humu.20601.View ArticlePubMedGoogle Scholar
  21. Andersen L, Ballester R, Marchuk D, Chang E, et al: A conserved alternative splice in the von Recklinghausen neurofibromatosis (NF1) gene produces two neurofibromin isoforms, both of which have GTPase-activating protein activity. Mol Cell Biol. 1993, 13: 487-495.PubMed CentralView ArticlePubMedGoogle Scholar
  22. Danglot G, Régnier V, Fauvet D, Vassal G, et al: Neurofibromatosis 1 (NF1) mRNAs expressed in the central nervous system are differentially spliced in the 5' part of the gene. Hum Mol Genet. 1995, 4: 915-920. 10.1093/hmg/4.5.915.View ArticlePubMedGoogle Scholar
  23. Kaufmann D, Müller R, Kenner O, Leistner W, et al: The N-terminal splice product NF1-10a-2 of the NF1 gene codes for a transmembrane segment. Biochem Biophys Res Commun. 2002, 294: 496-503. 10.1016/S0006-291X(02)00501-6.View ArticlePubMedGoogle Scholar
  24. Gutmann D, Geist R, Rose K, Wright D: Expression of two new protein isoforms of the neurofibromatosis type 1 gene product, neurofibromin, in muscle tissues. Dev Dyn. 1995, 202: 302-311. 10.1002/aja.1002020309.View ArticlePubMedGoogle Scholar
  25. Upadhyaya M: NF1 gene structure and NF1 genotype/phenotype correlations. Neurofibromatoses, Karger, Basel. Edited by: Kaufmann D. 2008, 46-62.View ArticleGoogle Scholar
  26. Bennett E, Thomas N, Upadhyaya M: Neurofibromatosis type 1: Its association with the Ras/MAPK pathway syndromes. J Paediatr Neurol. 2009, 7: 105-115.Google Scholar
  27. Cichowski K, Shih T, Schmitt E, Santiago S, et al: Mouse models of tumor development in neurofibromatosis type 1. Science. 1999, 286: 2172-2176. 10.1126/science.286.5447.2172.View ArticlePubMedGoogle Scholar
  28. Cichowski K, Jacks T: NF1 tumor suppressor gene function: Narrowing the GAP. Cell. 2001, 104: 593-604. 10.1016/S0092-8674(01)00245-8.View ArticlePubMedGoogle Scholar
  29. Serra E, Rosenbaum T, Winner U, Aledo R, et al: Schwann cells harbor the somatic NF1 mutation in neurofibromas: Evidence of two different Schwann cell subpopulations. Hum Mol Genet. 2000, 9: 3055-3064. 10.1093/hmg/9.20.3055.View ArticlePubMedGoogle Scholar
  30. Le L, Shipman T, Burns D, Parada L: Cell of origin and microenvironment contribution for NF1-associated dermal neurofibromas. Cell Stem Cell. 2009, 4: 453-463. 10.1016/j.stem.2009.03.017.PubMed CentralView ArticlePubMedGoogle Scholar
  31. McLaughlin ME, Jacks T: Progesterone receptor expression in neurofibromas. Cancer Res. 2003, 63: 752-755.PubMedGoogle Scholar
  32. Dugoff L, Sujansky E: Neurofibromatosis type 1 and pregnancy. Am J Med Genet. 1996, 66: 7-10. 10.1002/(SICI)1096-8628(19961202)66:1<7::AID-AJMG2>3.0.CO;2-R.View ArticlePubMedGoogle Scholar
  33. Roth T, Ramamurthy P, Muir D, Wallace M, et al: Influence of hormones and hormone metabolites on the growth of Schwann cells derived from embryonic stem cells and on tumor cell lines expressing variable levels of neurofibromin. Dev Dyn. 2008, 237: 513-524. 10.1002/dvdy.21430.View ArticlePubMedGoogle Scholar
  34. Wu J, Williams J, Rizvi T, Kordich J, et al: Plexiform and dermal neurofibromas and pigmentation are caused by Nf1 loss in desert hedgehog-expressing cells. Cancer Cell. 2008, 13: 105-116. 10.1016/j.ccr.2007.12.027.PubMed CentralView ArticlePubMedGoogle Scholar
  35. Joseph N, Mosher J, Buchstaller J, Snider P, et al: The loss of Nf1 transiently promotes self-renewal but not tumorigenesis by neural crest stem cells. Cancer Cell. 2008, 13: 129-140. 10.1016/j.ccr.2008.01.003.PubMed CentralView ArticlePubMedGoogle Scholar
  36. Parrinello S, Noon L, Harrisingh M, Digby P, et al: NF1 loss disrupts Schwann cell-axonal interactions: A novel role for sema-phorin 4F. Genes Dev. 2008, 22: 3335-3348. 10.1101/gad.490608.PubMed CentralView ArticlePubMedGoogle Scholar
  37. Zhu Y, Ghosh P, Charnay P, Burns D, et al: Neurofibromas in NF1: Schwann cell origin and role of tumor environment. Science. 2002, 296: 920-922. 10.1126/science.1068452.PubMed CentralView ArticlePubMedGoogle Scholar
  38. Ingram D, Yang F, Travers J, Wenning M, et al: Genetic and biochemical evidence that haploinsufficiency of the Nf1 tumor suppressor gene modulates melanocyte and mast cell fates in vivo. J Exp Med. 2000, 191: 181-188. 10.1084/jem.191.1.181.PubMed CentralView ArticlePubMedGoogle Scholar
  39. Yang FC, Ingram DA, Chen S, Zhu Y, et al: Nf1-dependent tumors require a microenvironment containing Nf1+/- and c-kit-dependent bone marrow. Cell. 2008, 135: 437-448. 10.1016/j.cell.2008.08.041.PubMed CentralView ArticlePubMedGoogle Scholar
  40. Serra E, Rosenbaum T, Nadal M, Winner U, et al: Mitotic recombination effects homozygosity for NF1 germline mutations in neurofibromas. Nat Genet. 2001, 28: 294-296. 10.1038/90148.View ArticlePubMedGoogle Scholar
  41. Thomas L, Kluwe L, Chuzhanova N, Mautner V, et al: Analysis of NF1 somatic mutations in cutaneous neurofibromas from patients with high tumor burden. Neurogenetics. 2010, 11: 391-400. 10.1007/s10048-010-0240-y.View ArticlePubMedGoogle Scholar
  42. Garcia-Linares C, Fernandez-Rodriguez J, Terribas E, Mercade J, et al: Dissecting loss of heterozygosity (LOH) in neurofibro-matosis type 1-associated neurofibromas: Importance of copy neutral LOH. Hum Mutat. 2011, 32: 78-90. 10.1002/humu.21387.PubMed CentralView ArticlePubMedGoogle Scholar
  43. Ducatman B, Scheithauer B, Piepgras D, Reiman H, et al: Malignant peripheral nerve sheath tumors. A clinicopathologic study of 120 cases. Cancer. 1986, 57: 2006-2021. 10.1002/1097-0142(19860515)57:10<2006::AID-CNCR2820571022>3.0.CO;2-6.View ArticlePubMedGoogle Scholar
  44. Evans D, Baser M, McGaughran J, Sharif S, et al: Malignant peripheral nerve sheath tumours in neurofibromatosis 1. J Med Genet. 2002, 39: 311-314. 10.1136/jmg.39.5.311.PubMed CentralView ArticlePubMedGoogle Scholar
  45. McCaughan J, Holloway S, Davidson R, Lam W: Further evidence of the increased risk for malignant peripheral nerve sheath tumour from a Scottish cohort of patients with neurofibromatosis type 1. J Med Genet. 2007, 44: 463-466. 10.1136/jmg.2006.048140.PubMed CentralView ArticlePubMedGoogle Scholar
  46. Spurlock G, Griffiths S, Uff J, Upadhyaya M: Somatic alterations of the NF1 gene in an NF1 individual with multiple benign tumours (internal and external) and malignant tumour types. Fam Cancer. 2007, 6: 463-471. 10.1007/s10689-007-9149-5.View ArticlePubMedGoogle Scholar
  47. Benz MR, Czernin J, Dry SM, Tap WD, et al: Quantitative F18-fluorodeoxyglucose positron emission tomography accurately characterizes peripheral nerve sheath tumors as malignant or benign. Cancer. 2010, 116: 451-458. 10.1002/cncr.24755.PubMed CentralView ArticlePubMedGoogle Scholar
  48. De Raedt T, Brems H, Wolkenstein P, Vidaud D, et al: Elevated risk for MPNST in NF1 microdeletion patients. Am J Hum Genet. 2003, 72: 1288-1292. 10.1086/374821.PubMed CentralView ArticlePubMedGoogle Scholar
  49. Upadhyaya M, Spurlock G, Majounie E, Griffiths S, et al: The heterogeneous nature of germline mutations in NF1 patients with malignant peripheral serve sheath tumours (MPNSTs). Hum Mutat. 2006, 27: 716-View ArticlePubMedGoogle Scholar
  50. Mautner VF, Kluwe L, Friedrich RE, Roehl AC, et al: Clinical characterisation of 29 neurofibromatosis type-1 patients with molecularly ascertained 1.4 Mb type-1 NF1 deletions. J Med Genet. 2010, 47: 623-630. 10.1136/jmg.2009.075937.View ArticlePubMedGoogle Scholar
  51. Pasmant E, Vidaud D, Harrison M, Upadhyaya M: Different sized somatic NF1 locus rearrangements in neurofibromatosis 1-associated malignant peripheral nerve sheath tumors. J Neurooncol. 2010, 102: 341-346.View ArticlePubMedGoogle Scholar
  52. Legius E, Dierick H, Wu R, Hall B, et al: TP53 mutations are frequent in malignant NF1 tumors. Genes Chromosomes Cancer. 1994, 10: 250-255. 10.1002/gcc.2870100405.View ArticlePubMedGoogle Scholar
  53. Menon A, Anderson K, Riccardi V, Chung R, et al: Chromosome 17p deletions and p53 gene mutations associated with the formation of malignant neurofibrosarcomas in von Recklinghausen neurofibromatosis. Proc Natl Acad Sci USA. 1990, 87: 5435-5439. 10.1073/pnas.87.14.5435.PubMed CentralView ArticlePubMedGoogle Scholar
  54. Vogel K, Klesse L, Velasco-Miguel S, Meyers K, et al: Mouse tumor model for neurofibromatosis type 1. Science. 1999, 286: 2176-2179. 10.1126/science.286.5447.2176.PubMed CentralView ArticlePubMedGoogle Scholar
  55. Kourea H, Orlow I, Scheithauer B, Cordon-Cardo C, et al: Deletions of the INK4A gene occur in malignant peripheral nerve sheath tumors but not in neurofibromas. Am J Pathol. 1999, 155: 1855-1860. 10.1016/S0002-9440(10)65504-6.PubMed CentralView ArticlePubMedGoogle Scholar
  56. Mantripragada K, Spurlock G, Kluwe L, Chuzhanova N, et al: High-resolution DNA copy number profiling of malignant peripheral nerve sheath tumors using targeted microarray-based comparative genomic hybridization. Clin Cancer Res. 2008, 14: 1015-1024. 10.1158/1078-0432.CCR-07-1305.View ArticlePubMedGoogle Scholar
  57. Nielsen G, Stemmer-Rachamimov A, Ino Y, Moller M, et al: Malignant transformation of neurofibromas in neurofibromatosis 1 is associated with CDKN2A/p16 inactivation. Am J Pathol. 1999, 155: 1879-1884. 10.1016/S0002-9440(10)65507-1.PubMed CentralView ArticlePubMedGoogle Scholar
  58. Gregorian C, Nakashima J, Dry S, Nghiemphu P, et al: PTEN dosage is essential for neurofibroma development and malignant transformation. Proc Natl Acad Sci USA. 2009, 106: 19479-19484. 10.1073/pnas.0910398106.PubMed CentralView ArticlePubMedGoogle Scholar
  59. Subramanian S, Thayanithy V, West R, Lee C, et al: Genome-wide transcriptome analyses reveal p53 inactivation mediated loss of miR-34a expression in malignant peripheral nerve sheath tumours. J Pathol. 2010, 220: 58-70. 10.1002/path.2633.PubMed CentralView ArticlePubMedGoogle Scholar
  60. Chai G, Liu N, Ma J, Li H, et al: MicroRNA-10b regulates tumorigenesis in neurofibromatosis type 1. Cancer Sci. 2010, 101: 1997-2004. 10.1111/j.1349-7006.2010.01616.x.View ArticlePubMedGoogle Scholar
  61. Ars E, Kruyer H, Gaona A, Casquero P, et al: A clinical variant of neurofibromatosis type 1: Familial spinal neurofibromatosis with a frameshift mutation in the NF1 gene. Am J Hum Genet. 1998, 62: 834-841. 10.1086/301803.PubMed CentralView ArticlePubMedGoogle Scholar
  62. Poyhonen M, Leisti E, Kytölä S, Leisti J: Hereditary spinal neurofibromatosis: A rare form of NF1?. J Med Genet. 1997, 34: 184-187. 10.1136/jmg.34.3.184.PubMed CentralView ArticlePubMedGoogle Scholar
  63. Pulst SM, Riccardi VM, Fain P, Korenberg JR: Familial spinal neurofibromatosis: Clinical and DNA linkage analysis. Neurology. 1991, 41: 1923-1927. 10.1212/WNL.41.12.1923.View ArticlePubMedGoogle Scholar
  64. Upadhyaya M, Spurlock G, Kluwe L, Chuzhanova N, et al: The spectrum of somatic and germline NF1 mutations in NF1 patients with spinal neurofibromas. Neurogenetics. 2009, 10: 251-263. 10.1007/s10048-009-0178-0.View ArticlePubMedGoogle Scholar
  65. Miettinen M, Fetsch J, Sobin L, Lasota J: Gastrointestinal stromal tumors in patients with neurofibromatosis 1: A clinicopathologic and molecular genetic study of 45 cases. Am J Surg Pathol. 2006, 30: 90-96. 10.1097/01.pas.0000176433.81079.bd.View ArticlePubMedGoogle Scholar
  66. Maertens O, Prenen H, Debiec-Rychter M, Wozniak A, et al: Molecular pathogenesis of multiple gastrointestinal stromal tumors in NF1 patients. Hum Mol Genet. 2006, 15: 1015-1023. 10.1093/hmg/ddl016.View ArticlePubMedGoogle Scholar
  67. Stewart W, Traynor JP, Cooke A, Griffiths S, et al: Gastric carcinoid: Germline and somatic mutation of the neurofibromatosis type 1 gene. Fam Cancer. 2007, 6: 147-152. 10.1007/s10689-006-9002-2.View ArticlePubMedGoogle Scholar
  68. Stiller C, Chessells J, Fitchett M: Neurofibromatosis and childhood leukaemia/lymphoma: a population-based UKCCSG study. Br J Cancer. 1994, 70: 969-972. 10.1038/bjc.1994.431.PubMed CentralView ArticlePubMedGoogle Scholar
  69. Flotho C, Steinemann D, Mullighan C, Neale G, et al: Genome-wide single-nucleotide polymorphism analysis in juvenile myelomonocytic leukemia identifies uniparental disomy surrounding the NF1 locus in cases associated with neurofibromatosis but not in cases with mutant RAS or PTPN11. Oncogene. 2007, 26: 5816-5821. 10.1038/sj.onc.1210361.View ArticlePubMedGoogle Scholar
  70. Yoshimi A, Kojima S, Hirano N: Juvenile myelomonocytic leukemia: Epidemiology, etiopathogenesis, diagnosis, and management considerations. Paediatr Drugs. 2010, 12: 11-21.View ArticlePubMedGoogle Scholar
  71. Sugimoto Y, Muramatsu H, Makishima H, Prince C, et al: Spectrum of molecular defects in juvenile myelomonocytic leukaemia includes ASXL1 mutations. Br J Haematol. 2009, 150: 83-87.Google Scholar
  72. Steinemann D, Arning L, Praulich I, Stuhrmann M, et al: Mitotic recombination and compound-heterozygous mutations are predominant NF1-inactivating mechanisms in children with juvenile myelo-monocytic leukemia and neurofibromatosis type 1. Haematologica. 2010, 95: 320-323. 10.3324/haematol.2009.010355.PubMed CentralView ArticlePubMedGoogle Scholar
  73. Chen JM, Cooper DN, Ferec C, Kehrer-Sawatzki H, et al: Genomic rearrangements in inherited disease and cancer. Semin Cancer Biol. 2010, 20: 222-233. 10.1016/j.semcancer.2010.05.007.View ArticlePubMedGoogle Scholar
  74. Stephens K, Weaver M, Leppig K, Maruyama K, et al: Interstitial uniparental isodisomy at clustered breakpoint intervals is a frequent mechanism of NF1 inactivation in myeloid malignancies. Blood. 2006, 108: 1684-1689. 10.1182/blood-2005-11-011486.PubMed CentralView ArticlePubMedGoogle Scholar
  75. Listernick R, Charrow J, Greenwald M, Mets M: Natural history of optic pathway tumors in children with neurofibroma-tosis type 1: A longitudinal study. J Pediatr. 1994, 125: 63-66. 10.1016/S0022-3476(94)70122-9.View ArticlePubMedGoogle Scholar
  76. Gutmann D, James C, Poyhonen M, Louis D, et al: Molecular analysis of astrocytomas presenting after age 10 in individuals with NF1. Neurology. 2003, 61: 1397-1400. 10.1212/WNL.61.10.1397.View ArticlePubMedGoogle Scholar
  77. Gutmann D, Donahoe J, Brown T, James C, et al: Loss of neurofibromatosis 1 (NF1) gene expression in NF1-associated pilocytic astrocytomas. Neuropathol Appl Neurobiol. 2000, 26: 361-367. 10.1046/j.1365-2990.2000.00258.x.View ArticlePubMedGoogle Scholar
  78. Bausch B, Borozdin W, Mautner VF, Hoffmann MM, et al: Germline NF1 mutational spectra and loss-of-heterozygosity analyses in patients with pheochromocytoma and neurofibromatosis type 1. J Clin Endocrinol Metab. 2007, 92: 2784-2792. 10.1210/jc.2006-2833.View ArticlePubMedGoogle Scholar
  79. Petri BJ, van Eijck CH, de Herder WW, Wagner A, et al: Phaeochromocytomas and sympathetic paragangliomas. Br J Surg. 2009, 96: 1381-1392. 10.1002/bjs.6821.View ArticlePubMedGoogle Scholar
  80. Brems H, Park C, Maertens O, Pemov A, et al: Glomus tumors in neurofibromatosis type 1: Genetic, functional, and clinical evidence of a novel association. Cancer Res. 2009, 69: 7393-7401. 10.1158/0008-5472.CAN-09-1752.PubMed CentralView ArticlePubMedGoogle Scholar
  81. Stenson PD, Ball E, Howells K, Phillips A, et al: Human Gene Mutation Database: Towards a comprehensive central mutation database. J Med Genet. 2008, 45: 124-126.View ArticlePubMedGoogle Scholar
  82. Ivanov D, Hamby SE, Stenson PD, Phillips AD, et al: Comparative analysis of germline and somatic microlesion mutational spectra in 17 human tumor suppressor genes. Hum Mutat. 2011, 32: 620-632. 10.1002/humu.21483.View ArticlePubMedGoogle Scholar
  83. Lee J, Wang J, Torbenson M, Lu Y, et al: Loss of SDHB and NF1 genes in a malignant phyllodes tumor of the breast as detected by oligo-array comparative genomic hybridization. Cancer Genet Cytogenet. 2010, 196: 179-183. 10.1016/j.cancergencyto.2009.09.005.View ArticlePubMedGoogle Scholar
  84. Gottfried O, Viskochil D, Fults D, Couldwell W: Molecular, genetic, and cellular pathogenesis of neurofibromas and surgical implications. Neurosurgery. 2006, 58: 1-16. 10.1227/01.NEU.0000190651.45384.8B. discussion 11-16View ArticlePubMedGoogle Scholar
  85. Lamlum H, Ilyas M, Rowan A, Clark S, et al: The type of somatic mutation at APC in familial adenomatous polyposis is determined by the site of the germline mutation: A new facet to Knudson's 'two-hit' hypothesis. Nat Med. 1999, 5: 1071-1075. 10.1038/12511.View ArticlePubMedGoogle Scholar
  86. Dworkin AM, Ridd K, Bautista D, Allain DC, et al: Germline variation controls the architecture of somatic alterations in tumors. PLoS Genet. 2010, 6: e1001136-10.1371/journal.pgen.1001136.PubMed CentralView ArticlePubMedGoogle Scholar
  87. Padmanabhan A, Lee J, Ismat F, Lu M, et al: Cardiac and vascular functions of the zebrafish orthologues of the type I neurofi-bromatosis gene NFI. Proc Natl Acad Sci USA. 2009, 106: 22305-22310. 10.1073/pnas.0901932106.PubMed CentralView ArticlePubMedGoogle Scholar

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