A novel neurofibromatosis type 1 (NF1) mutation in a patient with NF1 and pheochromocytoma.
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ABSTRACT:
SUBMITTER: Seo Y
PROVIDER: S-EPMC5768533 | biostudies-literature | 2018 Jan
REPOSITORIES: biostudies-literature
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A novel neurofibromatosis type 1 (<i>NF1</i>) mutation in a patient with <i>NF1</i> and pheochromocytoma.
Seo Yoorim Y Jeong Yeonjeong Y Kim Dong Yoon DY Choi Kyueun K Kim Eun Sook ES Moon Sung Dae SD Han Je Ho JH
The Korean journal of internal medicine 20171129 1
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Project description:BackgroundNeurofibromatosis type 1 is an autosomal dominant inherited disease and caused by NF1 gene mutation. Its clinical manifestations include multiple cafe´-au lait (CAL) spots, skinfold freckling, neurofibroma, bone dysplasia, learning disabilities, and an increased risk of malignancy.Methods and resultsHere, we reported a Chinese patient bearing with a novel NF1 mutation (c.2064delGGATGCAGCGG/p.Gly672AsnfsTer24) and complaining mainly about bone phenotype. Functional studies found that this novel mutation caused the damage of NF1 mRNA and protein levels, and lost the inhibition on Ras/Erk signaling.ConclusionA novel mutation in NF1 gene was identified and in vitro functional studies were performed, which provided a potential molecular mechanism to explain the bone maldevelopment of patients with neurofibromatosis type 1.
| S-EPMC8172195 | biostudies-literature
Project description:Neurofibromatosis type 1 (NF1) (MIM#162200) is a relatively frequent genetic condition that predisposes to tumor formation. The main types of tumors occurring in NF1 patients are cutaneous and subcutaneous neurofibromas, plexiform neurofibromas, optic pathway gliomas, and malignant peripheral nerve sheath tumors. To search for somatic mutations in cutaneous (dermal) neurofibromas, whole-exome sequencing (WES) was performed on seven spatially separated tumors and two reference tissues (blood and unaffected skin) from a single NF1 patient. Validation of WES findings was done using routine Sanger sequencing or Sequenom IPlex SNP genotyping. Exome sequencing confirmed the existence of a known familial splice-site mutation NM_000267.3:c.3113+1G>A in exon 23 of NF1 gene (HGMD ID CS951480) in blood, unaffected skin, and all tumor samples. In five out of seven analyzed tumors, we additionally detected second-hit mutations in the NF1 gene. Four of them were novel and one was previously observed. Each mutation was distinct, demonstrating the independent origin of each tumor. Only in two of seven tumors we detected an additional somatic mutation that was not associated with NF1. Our study demonstrated that somatic mutations of NF1 are likely the main drivers of cutaneous tumor formation. The study provides evidence for the rareness of single base pair level alterations in the exomes of benign NF1 cutaneous tumors.
| S-EPMC4795057 | biostudies-literature
Project description:BackgroundPlexiform neurofibromas represent a common neoplasia of type 1 neurofibromatosis in which neurofibromas arise from multiple nerves involving connective tissue and skin and rarely affect the colon and rectum. Co-occurrence of plexiform neurofibromas, neuroendocrine tumors with primary involvement of the rectum, and medullary thyroid carcinoma in patients with neurofibromatosis type 1 is a previously undescribed condition. The aim of this manuscript was to present a case of primary plexiform neurofibroma and neuroendocrine tumors of the upper rectum in a patient with neurofibromatosis type 1 whose genetic sequencing found a novel mutation in the neurofibromatosis type 1 gene and to review the literature.Case reportA 49-year-old woman with a familial history of neurofibromatosis type 1 complained of abdominal cramps for 6 months. She had previously been submitted for a total thyroidectomy due to medullary thyroid carcinoma. She was submitted to a colonoscopy, which identified a submucosa lesion located in the upper rectum. The patient was referred for a laparoscopic rectosigmoidectomy, and the histopathological study of the surgical specimen identified two different tumors. An immunohistochemical panel was done for histopathological confirmation of the etiology of both lesions. The results of the panel showed intense immunoexpression of S100 protein in the largest and superficial lesion, as well as positivity for chromogranin and synaptophysin in the minor and deep lesion confirming the diagnosis of rectal plexiform neurofibromas concomitant with neuroendocrine tumors. The proliferative activity rate using Ki-67 antibodies showed that both tumors had a low rate of mitotic activity (<1%). Genetic sequence panel identified an undescribed mutation in the neurofibromatosis type 1 gene (deletion, exons 2-30). The patient's postoperative evolution was uneventful, and she remains well, without recurrence, 3 years after surgery.ConclusionThe co-occurrence of medullary thyroid carcinoma, plexiform neurofibromas, and neuroendocrine tumors of the rectum in patients with neurofibromatosis type 1 is an exceptional and undescribed possibility, whose diagnosis can be confirmed by the immunohistochemical staining and genetic panel.
| S-EPMC9831629 | biostudies-literature
Project description:One of the major primary features of the neurocutaneous genetic disorder Neurofibromatosis type 1 are the hyperpigmentary café-au-lait macules where dysregulation of melanocyte development, proliferation and differentiation is considered to play a key etiopathogenic role. To gain better insight in the possible role of the tumor suppressor gene NF1, a transcriptomic microarray analysis was performed on human NF1 heterozygous (NF1+/-) melanocytes of a Neurofibromatosis type 1 patient and NF1 wild type (NF1+/+) melanocytes of a healthy control patient, both cultured from normally pigmented and hyperpigmented lesional café-au-lait skin. Out of 13,850 unique genes, a total of 137 had a significant twofold or more up- (72) or down-regulated (65) expression in NF1+/- melanocytes compared to NF1+/+ melanocytes (genotype effect). Considering possible intrinsic genetic variation in lesional skin, melanocytes showed a total of 51 genes having a significant twofold or more up- (37) or down-regulated (14) expression when they were cultured from hyperpigmentary café-au-lait skin compared to normally pigmented skin (lesional skin type effect). NF1+/- café-au-lait skin melanocytes showed 468 genes with a significant two-fold or more up- (183) or down-regulated (285) expression going beyond the sum of the separate main effects (interaction). Detailed analysis enabled the identification of several modulated genes in NF1+/- (café-au-lait skin) melanocytes, mainly involved in controlling cell proliferation and cell maintenance, in cell adhesion and, surprisingly, in the immune response. An interesting finding was that a high number of transcription factor genes were differentially modulated, among which a specific subset - important in melanocyte-lineage development - showed downregulation in a transcriptional cis-regulatory network governing the activation of the melanocyte-specific dopachrome tautomerase (DCT) gene.
2005-02-05 | E-MEXP-258 | biostudies-arrayexpress
Project description:BackgroundSpinal neurofibromatosis (SNF) is a related form of Neurofibromatosis type 1 (NF1) with a low incidence. Here, we report a SNF patient with NF1 (OMIM *613113) mutation in a classic NF1 family to enrich the case data.MethodsWe presented the clinical data of a 27-year-old female suffered from SNF. Two NF1 individuals (the mother and the brother) in the patient's family were also described. In the SNF patient, tumors in cervical were removed by surgical operation after the spinal MRI evaluation. Hematoxylin-eosin staining and immunohistochemistry were performed to better characterize the excised tumors. NF1 exons of the patient and her NF1 families were further sequenced by the next-generation sequencing technology.ResultsThe patient developed irregular café-au-lait macules, multi-subcutaneous nodules, recurrent numbness, and weakness of both lower extremities. Multiple neurofibromas were found in the whole spine by spinal MRI. Tumor-like cells and hyperplasia of ganglion cells were found in the excised tissue by H&E staining and immunohistochemistry, respectively. One-year follow-up on the SNF patient showed that after the surgery lower limb pain, numbness and convulsion were completely relieved. A common germ-line pathogenic mutation (NM_000267.3:c.1721 + 3A>G) was found in both the SNF patient and her classic NF1 families.ConclusionA case of SNF with classic NF1 mutation in a classic NF1 family was identified for the first time, indicating that SNF may share the same gene mutation with NF1, while the different manifestation of NF1 and SNF may be related to gene modification.
| S-EPMC6978228 | biostudies-literature
Project description:Low-grade brain tumors (pilocytic astrocytomas) arising in the neurofibromatosis type 1 (NF1) inherited cancer predisposition syndrome are hypothesized to result from a combination of germline and acquired somatic NF1 tumor suppressor gene mutations. However, genetically engineered mice (GEM) in which mono-allelic germline Nf1 gene loss is coupled with bi-allelic somatic (glial progenitor cell) Nf1 gene inactivation develop brain tumors that do not fully recapitulate the neuropathological features of the human condition. These observations raise the intriguing possibility that, while loss of neurofibromin function is necessary for NF1-associated low-grade astrocytoma development, additional genetic changes may be required for full penetrance of the human brain tumor phenotype. To identify these potential cooperating genetic mutations, we performed whole-genome sequencing (WGS) analysis of three NF1-associated pilocytic astrocytoma (PA) tumors. We found that the mechanism of somatic NF1 loss was different in each tumor (frameshift mutation, loss of heterozygosity, and methylation). In addition, tumor purity analysis revealed that these tumors had a high proportion of stromal cells, such that only 50%-60% of cells in the tumor mass exhibited somatic NF1 loss. Importantly, we identified no additional recurrent pathogenic somatic mutations, supporting a model in which neuroglial progenitor cell NF1 loss is likely sufficient for PA formation in cooperation with a proper stromal environment.
| S-EPMC3589532 | biostudies-literature
Project description:Cancer predisposition syndromes mediated by recessive cancer genes generate tumors via somatic variants (second hits) in the unaffected allele. Second hits may or may not be sufficient for neoplastic transformation. Here we performed whole-genome and whole-exome sequencing on 479 tissue biopsies from a child with neurofibromatosis type 1, a multisystem cancer-predisposing syndrome mediated by constitutive monoallelic NF1 inactivation. We identified multiple independent NF1 driver variants in histologically normal tissues, but not in 610 biopsies from two nonpredisposed children. We corroborated this finding using targeted duplex sequencing, including a further nine adults with the same syndrome. Overall, truncating NF1 mutations were under positive selection in normal tissues from individuals with neurofibromatosis type 1. We demonstrate that normal tissues in neurofibromatosis type 1 commonly harbor second hits in NF1, the extent and pattern of which may underpin the syndrome's cancer phenotype.
| S-EPMC11906363 | biostudies-literature
Project description:Neurofibromatosis type 1 (NF1) is an autosomal dominant genetic condition with complete age-dependent penetrance, variable expressivity and a global prevalence of ∼1/3,000. It is characteriszed by numerous café-au-lait macules, skin freckling in the inguinal or axillary regions, Lisch nodules of the iris, optic gliomas, neurofibromas, and tumour predisposition. The diagnostic testing strategy for NF1 includes testing for DNA single nucleotide variants (SNVs), copy number variants (CNVs) as well as RNA analysis for deep intronic and splice variants, which can cumulatively identify the causative variant in 95% of patients. In the present study, NF1 patients were screened using a next-generation sequencing (NGS) assay targeting NF1 exons and intron/exon boundaries for SNV and NF1 multiple ligation-dependent probe amplification (MLPA) analysis for CNV detection. Twenty-six unrelated Southern African patients clinically suspected of having NF1, based on the clinical diagnostic criteria developed by the National Institute of Health (NIH), were included in the current study. A detection rate of 58% (15/26) was obtained, with SNVs identified in 80% (12/15) using a targeted gene panel and NF1 gene deletion in 20% (3/15) identified using MLPA. Ten patients (38%) had no variants identified, although they met NF1 diagnostic criteria. One VUS was identified in this study in a patient that met NF1 diagnostic criteria, however there was no sufficient information to classify variant as pathogenic. The clinical features of Southern African patients with NF1 are similar to that of the known NF1 phenotype, with the exception of a lower frequency of plexiform neurofibromas and a higher frequency of developmental/intellectual disability compared to other cohorts. This is the first clinical and molecular characterisation of a Southern African ancestry NF1 cohort using both next-generation sequencing and MLPA analysis. A significant number of patients remained without a diagnosis following DNA-level testing. The current study offers a potential molecular testing strategy for our low resource environment that could benefit a significant proportion of patients who previously only received a clinical diagnosis without molecular confirmation.
| S-EPMC11002079 | biostudies-literature
Project description:BackgroundMutations in RAB39B at Xq28 causes a rare form of X-linked intellectual disability (ID) and Parkinson's disease. Neurofibromatosis type 1 (NF1) is caused by heterozygous mutations in NF1 occurring de novo in about 50% of cases, usually due to paternal gonadal mutations. This case report describes clinical and genetic findings in a boy with the occurrence of two distinct causative mutations in NF1 and RAB39B explaining the observed phenotype.Case presentationHere we report a 7-year-old boy with multiple café-au-lait macules (CALMs) and freckling, severe macrocephaly, peculiar facial gestalt, severe ID with absent speech, epilepsy, autistic traits, self-harming, and aggressiveness. Proband is an only child born to a father aged 47. Parents did not present signs of NF1, while a maternal uncle showed severe ID, epilepsy, and tremors.By RNA analysis of NF1, we identified a de novo splicing variant (NM_000267.3:c.6579+2T>C) in proband, which explained NF1 clinical features but not the severe ID, behavioral problems, and aggressiveness. Family history suggested an X-linked condition and massively parallel sequencing of X-exome identified a novel RAB39B mutation (NM_171998.2:c.436_447del) in proband, his mother, and affected maternal uncle, subsequently validated by Sanger sequencing in these and other family members.ConclusionsThe case presented here highlights how concurrent genetic defects should be considered in NF1 patients when NF1 mutations cannot reasonably explain all the observed clinical features.
| S-EPMC7460788 | biostudies-literature
Project description:A synchronous case of small bowel adenocarcinoma(SAB) is reported, accompanied with gastrointestinal stromal tumor(GIST),and gangliocytomain in an elderly woman with neurofibromatosis type 1 (NF-1). A 67-year-old female was hospitalized with the chief complaint of abdominal pain, the computed tomography scan indicated a large bowel mass. Multiple tumors were found in the small intestine, through which two larger tumors (7 cm and 1.5 cm) were resected. A novel germline NF1 mutation and a PMS2 mutation were identified after genetic testing, followed by the exploration of possible relationship between them in promoting tumorigenesis. Our results suggest multiple gastrointestinal tumors emerging in NF1 patients, and genetic testing can better guide postoperative treatment in a more efficient way.
| S-EPMC9815498 | biostudies-literature