Analysis of NF1 gene variants among thirteen patients with neurofibromatosis type 1 / 中华医学遗传学杂志

OBJECTIVE@#To detect variants of NF1 gene among thirteen patients with neurofibromatosis type 1.@*METHODS@#Genomic DNA was extracted from peripheral blood samples of the patients. High-throughput sequencing was employed to detect potential variants of the NF1 and NF2 genes.@*RESULTS@#Thirteen pathogenic variants were identified among the patients, which included one NF1 deletion, three missense variants, three nonsense variants and six frameshifting variants. Among these, 10 variants have been associated with neurofibromatosis type 1. c.4180A>T (p.Asn1394Tyr), c.4217dupT (p.Leu1406fs) and c.1753dupT(p.Leu585Phefs*3) were unreported previously. Based on the guidelines of the American College of Medical Genetics and Genomics, c.4180A>T (p.Asn1394Tyr) was predicted to be likely pathogenic (PS2+PM1+PM2+PP2), while c.4217dupT (p.Leu1406fs) and c.1753dupT (p.Leu585Phefs*3) were predicted to be pathogenic (PVS1+PS2+PM2).@*CONCLUSION@#Variants of the NF1 gene probably underlay the disease among these children. Above findings have enriched the the spectrum of NF1 gene variants.

Identification of a novel NF1 mutation in a Chinese family affected with neurofibromatosis type I / 中华医学遗传学杂志

OBJECTIVE@#To explore the molecular basis for a Chinese family affected with neurofibromatosis type I.@*METHODS@#Peripheral blood samples were collected from the proband and his parents. Potential mutations of NF1 gene were screened by PCR and Sanger sequencing. Pathogenicity of candidate mutations was analyzed using Polyphen-2 and Provean software.@*RESULTS@#Two mutations of the NF1 gene, including c.702G>A (synonymous mutation) and c.1733T>G (missense mutation), were discovered in the proband. Neither mutation was found in his parents and 50 healthy controls. Bioinformatics analysis indicated that the c.1733T>G mutation (p.Leu578Arg) was probably damaging. The affected codon L578 is highly conserved across various species.@*CONCLUSION@#The c.1733T>C mutation of the NF1 gene probably underlies the neurofibromatosis type I in this family.

A case of growth hormone deficiency combined with neurofibromatosis Type 1 and its gene analysis / 中南大学学报(医学版)

Neurofibromatosis Type 1 (NF1) is an autosomal dominant genetic disorder caused by NF1 gene mutations. Café au lait spots, neurofibromatosis, Lisch nodules, axillary freckling, dermal neurofibromas and skeletal dysplasia are the most common manifestations for this disease. A 11-year-old boy visited Third Xiangya Hospital, Central South University due to growth-retardation. He was eventually diagnosed as NF1 with growth hormone deficiency. A novel heterozygous splicing mutation c.6579+2 T>C (IVS 34+2 T>C) of NF1 gene was identified in the patient and his mother. Considering NF1 may present with short stature due to growth hormone deficiency, all children with short stature combined with café au lait spots should be screened for NF1, which may assist the clinical diagnosis and the genetic counseling.

A Case Report of Precocious Puberty in Children Associated with Hypothalamic Hamartoma in Neurofibromatosis Type 1 / 대한소아신경학회지

Neurofibromatosis type 1 (NF1) is a common neurocutaneous syndrome that presents with multiple café-au-lait spots, skinfold freckling, dermatofibromas, neurofibromas, and Lisch nodules. Mutations of the NF1 gene, encoding the protein neurofibromin, have been identified as the cause of this disease. NF1 can also present with precocious puberty and be associated with optic pathway tumors. Hypothalamic hamartoma as the cause of precocious puberty in patients with NF1 has been rarely described in the literature. Here, we report the findings for a patient with NF1 and precocious puberty associated with a hypothalamic hamartoma who had a newly discovered 14-bp deletion mutation in exon 5 of NF1. To our knowledge, this is the first time this combination is reported in the literature.

Mutation of the NF1 Gene and the Associated Clinical Features in Family Members with Neurofibromatosis Type 1 / 대한내과학회지

With an incidence of 1 per 2,500-3,000 individuals, neurofibromatosis type 1 (NF1) is the most common autosomal dominant disorder in humans. NF1 is caused by germline mutations of the NF1 gene, but to date genotype-phenotype analyses have indicated no clear relationship between specific gene mutations and the clinical features of this disease, even among family members with the same mutation. The present study describes a case of two siblings with NF1 with the same genetic mutation but different clinical manifestations. The first patient was a female with iris Lisch nodules, an adrenal incidentaloma, Graves' disease, and skin manifestations, while the second patient, the first patient's younger brother, exhibited only skin neurofibromas and freckling. Further study is needed to reveal the molecular processes underlying gene expression and phenotypes. A better understanding of the genetics associated with NF1 will allow clinicians to detect complications earlier and provide better genetic counseling to NF1 families.

Neurofibromatosis tipo 1 (NF1) y su diagnóstico molecular como estrategia del diagnóstico diferencial y a edades tempranas / Molecular diagnosis as a strategy for differential diagnosis and at early ages of neurofibromatosis type 1 (NF1)

Neurofibromatosis type 1 (NF1), is a haploinsufficient and multisystemic disease, caused by inherited or sporadic mutations in the NF1 gene. Its incidence is one in 2,500 to 3,000 individuals, it has an autosomal dominant pattern of inheritance, high clinical variability, complete penetrance and age-dependent complications. Neurofibromin is the product of the NF1 gene and is believed to act as a tumor suppressor since the loss of its function has been associated with benign and malignant tumors in neural crest-derived tissues. Only two correlations between clinical phenotype and mutant alleles in the NF1 gene have been observed. The established criteria for disease diagnosis are very efficient in adults and children older than 3 years of age, but not for children under this age. Mutational analysis is therefore recommended to confirm the disease in young children with a negative family history. A pathogenic mutation in the NF1 should be added to the list of diagnostic criteria. Mutational analysis is also recommended for differential diagnosis and for prenatal or pre-implantation genetic diagnosis, taking into consideration the family history and the type of method to be applied. Molecular studies of this disease using different complimentary molecular techniques and bioinformatics tools have characterized NF1 gene mutations at both the DNA and mRNA levels, increasing the mutational spectrum. Consequently, about 1,289 defects have been reported to date, mainly nonsense/missense mutations, deletions and splice site defects.

Early-Onset Breast Cancer in a Family with Neurofibromatosis Type 1 Associated with a Germline Mutation in BRCA1 / 한국유방암학회지

Neurofibromatosis type 1 (NF1), which may occur as an autosom-al dominant disorder, is caused by the absence of neurofibromin protein due to somatic mutations in the NF1 gene, and it has been associated with an increased risk of breast cancer. Herein we describe a family with two women affected by both NF1 and early-onset breast cancer. We evaluated whether the concomitance of NF1 and early-onset breast cancer could be due to disease-causing mutations in both NF1 and BRCA1 gene in a Korean family with clinical features of both NF1 and hereditary breast cancer. Mutation analyses identified nonsense mutations in NF1 and BRCA1 genes. Our findings indicate that an awareness of the possible concomitance of NF1 and BRCA1 gene mutations is important for identifying the genetic origin of early-onset breast cancer in patients with NF1 to achieve early detection of cancers and decrease breast cancer-associated morbidity and mortality in these patients.

Neurofibromatosis type 1: a single center's experience in Korea / 소아과

PURPOSE: Neurofibromatosis 1 (NF1) is an autosomal dominant condition caused by an NF1 gene mutation. NF1 is also a multisystem disorder that primarily affects the skin and nervous system. The goal of this study was to delineate the phenotypic characterization and assess the NF1 mutational spectrum in patients with NF1. METHODS: A total of 42 patients, 14 females and 28 males, were enrolled in this study. Clinical manifestations and results of the genetic study were retrospectively reviewed. RESULTS: Age of the patients at the time of NF1 diagnosis was 15.8+/-14.6 years (range, 1-62 years). Twelve patients (28.6%) had a family history of NF1. Among the 42 patients, Cafe-au-lait spots were shown in 42 (100%), neurofibroma in 31 (73.8%), freckling in 22 (52.4%), and Lisch nodules in seven (16.7%). The most common abnormal finding in the brain was hamartoma (20%). Mental retardation was observed in five patients (11.9%), seizures in one patient (2.4%), and plexiform neurofibromas (PNFs) in four patients (9.5%). One patient with PNFs died due to a malignant peripheral nerve sheath tumor in the chest cavity. Genetic analysis of seven patients identified six single base substitutions (three missense and three nonsense) and one small deletion. Among these mutations, five (71.4%) were novel (two missense mutations: p.Leu1773Pro, p.His1170Leu; two nonsense mutations: p.Arg2517*, p.Cys2371*; one small deletion: p.Leu1944Phefs*6). CONCLUSION: The clinical characteristics of 42 Korean patients with NF1 were extremely variable and the mutations of the NF1 gene were genetically heterogeneous with a high mutation-detection rate.

A Terapia hormonal em pacientes com neurofibromatose tipo 1 é segura? / Hormonal therapy in patientes with neurofibromatosis type 1 is safe?

Nos pacientes com neurofibromatose tipo 1 (NF1), o número de neurofibromas varia grandemente de pessoa para pessoa, mesmo em casos intrafamiliares, com a mesma mutação na linhagem germinativa no gene NF1. Além das mutações nesse gene, provavelmente fatores adicionais são importantes no desenvolvimento ou no crescimento dos neurofibromas. O objetivo deste artigo é revisar a literatura sobre o papel dos hormônios no desenvolvimento e crescimento dos neurofibromas e a segurança da terapia hormonal nos pacientes com NF1

In patients with neurofibromatosis type 1 (NF1), the number of neurofibromas varies greatly from person to person, even in intrafamilial cases, with the same germline mutation in the NF1 gene. In addition to the mutations in this gene, it is likely that additional factors are important in neurofibroma development or growth. The purpose of this article is to review the literature on the role of hormones in the development and growth of neurofibromas and the safety of hormonal therapy in patients with NF1

Gastrointestinal Stromal Tumors in a Patient with Neurofibromatosis Type 1 / 대한내과학회지

Neurofibromatosis type 1 (NF1) is a genetic disease characterized by neoplastic and non-neoplastic disorders involving tissues of neuroectodermal and mesenchymal origin. NF1 is caused by mutations in the NF1 gene, which is found on chromosome 17q11.2. Patients with NF1 are at increased risk of developing soft tissue sarcomas that arise within the stromal compartment of the gastrointestinal tract, termed gastrointestinal stromal tumors (GISTs). GISTs associated with neurofibromatosis differ from sporadic GISTs, particularly with respect to their lower response rate to imatinib. We recently experienced a case involving a 45-year-old man with NF1 who was admitted to the hospital with epigastric pain and vomiting. Abdominal computed tomography revealed a duodenal GIST with pancreatic invasion. He had a base substitution mutation involving replacement of 2041 cytosine with thymine. He was treated successfully with a surgical operation and adjuvant imatinib therapy.

Gastrointestinal Stromal Tumors in a Patient with Neurofibromatosis Type 1 / 대한내과학회지

Neurofibromatosis type 1 (NF1) is a genetic disease characterized by neoplastic and non-neoplastic disorders involving tissues of neuroectodermal and mesenchymal origin. NF1 is caused by mutations in the NF1 gene, which is found on chromosome 17q11.2. Patients with NF1 are at increased risk of developing soft tissue sarcomas that arise within the stromal compartment of the gastrointestinal tract, termed gastrointestinal stromal tumors (GISTs). GISTs associated with neurofibromatosis differ from sporadic GISTs, particularly with respect to their lower response rate to imatinib. We recently experienced a case involving a 45-year-old man with NF1 who was admitted to the hospital with epigastric pain and vomiting. Abdominal computed tomography revealed a duodenal GIST with pancreatic invasion. He had a base substitution mutation involving replacement of 2041 cytosine with thymine. He was treated successfully with a surgical operation and adjuvant imatinib therapy.

Abordaje clínico de variantes fenotípicas en neurofibromatosis de tipo 1 / Clinical approach of phenotype variants in neurofibromatosis type 1

La neurofibromatosis de tipo 1 es una enfermedad genética de herencia autosómica dominante, de afectación multisistémica y gran variabilidad fenotípica, causada por una mutación del gen NF1 localizada en el cromosoma 17 q11.2 que afecta la codificación de la neurofibromina. La prevalencia mundial se estima en 1 de cada 4.000 a 5.000 individuos. En Colombia se desconoce su prevalencia. Los criterios diagnósticos establecidos por los National Institutes of Health incrementaron la sensibilidad diagnóstica para pacientes con neurofibromatosis de tipo 1, quienes presentan manifestaciones clínicas cutáneas y extracutáneas, para las cuales se propone una clasificación en siete grupos, según el sistema u órgano afectado, y en tres tipos de variantes clínicas: tumores, alteraciones esqueléticas y alteraciones oftalmológicas. Se describe la disponibilidad de pruebas diagnósticas y asesoría genética.

Identification of a mosaic mutation of NF1 gene in a sporadic case of neurofibromatosis type 1 / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To detect NF1 gene mutation in a patient with neurofibromatosis type 1.</p><p><b>METHODS</b>Five fragments encompassing the entire coding sequence of the NF1 gene were amplified with reverse transcription PCR. PCR products were directly sequenced. Suspected mutations were verified by sequencing of DNA amplified by PCR using genomic DNA as template. Corresponding exon of family members was also sequenced. Furthermore, the PCR products were inserted into a pGEM-T cloning vector to quantify cells carrying the mutation in different samples derived from the three embryonic layers.</p><p><b>RESULTS</b>The proband's clinical manifestation was consistent with neurofibromatosis type 1. Sequence analysis has identified a novel heterozygous mutation c.7911 C to T (p.Q2510X) in exon 51 of the NF1 gene in the proband. The same mutation was also detected in peripheral blood cells, uroepithelial cells and oral mucosal cells of the proband, though the signals of uroepithelial cells were significantly weaker. By T cloning-sequencing, recombinants carrying the NF1 gene mutation respectively accounted for 42%, 36% and 12% of all peripheral blood cells, oral mucosal cells and uroepithelial cells .</p><p><b>CONCLUSION</b>It is likely that a mutation of NF1 gene has occurred in early embryogenesis of the proband, which in turn has led to generalized mosaicism of neurofibromatosis type 1.</p>

Correlation Between Unidentified Bright Objects on Brain Magnetic Resonance Imaging (MRI) and Cerebral Glucose Metabolism in Patients with Neurofibromatosis Type 1

PURPOSE: Neurofibromatosis type 1 (NF1), which is caused by mutations of the NF1 gene, is the most frequent single gene disorder to affect the nervous system. Unidentified bright objects (UBOs) are commonly observed on brain magnetic resonance imaging (MRI) in patients with NF1. However, their clinical and pathologic significance is not well understood. The purpose of this study was to investigate the correlation between UBOs and cerebral glucose metabolism measured by 18F-2-Fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography (PET) in Korean patients with NF1. MATERIALS AND METHODS: Medical records of 75 patients (34 males and 41 females) with NF1 who underwent brain MRI and PET between 2005 and 2011 were evaluated retrospectively. Clinical data including demographics, neurological symptoms, and brain MRI and PET findings, were reviewed. RESULTS: UBOs were detected in the brain MRI scans of 31 patients (41%). The region most frequently affected by UBOs was the basal ganglia. The most frequent brain PET finding was thalamic glucose hypometabolism (45/75, 60%). Of the 31 patients with UBOs, 26 had thalamic glucose hypometabolism on brain PET, but the other 5 had normal brain PET findings. Conversely, of the 45 patients with thalamic glucose hypometabolism on brain PET, 26 showed UBOs on their brain MRI scans, but 19 had normal findings on brain MRI scans. CONCLUSION: UBOs on brain MRI scans and thalamic glucose hypometabolism on PET appear to be 2 distinctive features of NF1 rather than correlated symptoms. Because the clinical significance of these abnormal imaging findings remains unclear, a longitudinal follow-up study of changes in clinical manifestations and imaging findings is necessary.

Correlation Between Unidentified Bright Objects on Brain Magnetic Resonance Imaging (MRI) and Cerebral Glucose Metabolism in Patients with Neurofibromatosis Type 1

PURPOSE: Neurofibromatosis type 1 (NF1), which is caused by mutations of the NF1 gene, is the most frequent single gene disorder to affect the nervous system. Unidentified bright objects (UBOs) are commonly observed on brain magnetic resonance imaging (MRI) in patients with NF1. However, their clinical and pathologic significance is not well understood. The purpose of this study was to investigate the correlation between UBOs and cerebral glucose metabolism measured by 18F-2-Fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography (PET) in Korean patients with NF1. MATERIALS AND METHODS: Medical records of 75 patients (34 males and 41 females) with NF1 who underwent brain MRI and PET between 2005 and 2011 were evaluated retrospectively. Clinical data including demographics, neurological symptoms, and brain MRI and PET findings, were reviewed. RESULTS: UBOs were detected in the brain MRI scans of 31 patients (41%). The region most frequently affected by UBOs was the basal ganglia. The most frequent brain PET finding was thalamic glucose hypometabolism (45/75, 60%). Of the 31 patients with UBOs, 26 had thalamic glucose hypometabolism on brain PET, but the other 5 had normal brain PET findings. Conversely, of the 45 patients with thalamic glucose hypometabolism on brain PET, 26 showed UBOs on their brain MRI scans, but 19 had normal findings on brain MRI scans. CONCLUSION: UBOs on brain MRI scans and thalamic glucose hypometabolism on PET appear to be 2 distinctive features of NF1 rather than correlated symptoms. Because the clinical significance of these abnormal imaging findings remains unclear, a longitudinal follow-up study of changes in clinical manifestations and imaging findings is necessary.

Mutational Analysis of the NF1 Gene in Two Families with Neurofibromatosis 1 Accompanied by Pheochromocytoma

Neurofibromatosis type 1 (NF1) is one of the most common autosomal dominant inherited disorders affecting the nervous system. NF1 is associated with mutations in the NF1 gene, which is located on chromosome sub-band 17q11.2 and contains 57 exons spanning approximately 300 kb of genomic DNA. NF1 is caused by a loss of function mutation of the NF1 gene, a tumor suppressor gene, which encodes for neurofibromin, a GTPase-activating protein (GAP) involved in the negative regulation of Ras activity. The GAP-related domain, which is encoded for by exons 20-27a, is one of the most important functional domains in neurofibromin. The cysteine-serine-rich domain has been recognized as an important functional domain in NF1-related pheochromocytomas. As the result of many genetic analyses of NF1-related pheochromocytomas, pheochromocytoma has generally been recognized as a true component of NF1. We recently experienced two families with NF1 accompanied by pheochromocytoma. The proband of family 1 is a 31-year-old female diagnosed with NF1 and pheochromocytoma. Gene analysis of the proband and her sister showed that the mutation of the NF1 gene (c.7907+1G>A) led to the skipping of exon 53 during NF1 mRNA splicing. The proband of family 2 is a 48-year-old male who was diagnosed with the same condition. Gene analysis demonstrated the mutation of the NF1 gene (c.5206-8C>G) with missplicing of exon 37. These novel germline mutations did not fall into the GAP-related nor the cysteine-serine-rich domains, but into the C-terminal area of the NF1 gene. This suggests that the correlation between the genotype and phenotype of NF1-related pheochromocytoma is somewhat difficult to characterize. Further studies will be necessary to confirm the function of the C-terminal area of the NF1 gene and its contribution to the development of NF1 and pheochromocytoma.

Neurofibromatose tipo 1: revisão atualizada dos critérios diagnósticos / Neurofibromatosis type 1: updated revision of diagnoses criteria

A neurofibromatose tipo 1 (NF1), também denominada doença de von Recklinghausen, é multissistêmica. É uma das mais freqüentes doenças genéticas autossômicas dominandes, afetando um em cada 2 mil a 4 mil indivíduos. Metade dos portadores de NF1 apresenta uma nova mutação no gene NF1. As manifestações da doença são extremamente variadas, e os critérios de diagnósticos são: a. seis ou mais manchas café-com-leite maiores que 5mm em pós-púberes; b. dois ou mais neurofibromas de qualquer tipo ou um neurofibroma plexiforme; c. múltiplas sardas axilares ou inguinais; d. displasia do esfenóide ou afilamento do córtex de ossos longos com ou sem pseudo-artrose; e. glioma óptico; f. dois ou mais hamartomas de íris (nódulos de Lisch); g. parente de primeiro grau portador de NF1 com diagnóstico firmado através dos critérios acima. Crises epilépticas, dificuldade escolar e deficiência mental leve são freqüentes nestes pacientes. A NF1 é uma doença progressiva que pode piorar com a idade. O objetivo deste artigo é rever os critérios diagnósticos da NF1.

Neurofibromatosis type 1 (NF1), also known as von Recklinghausen disease, is a multisystemic disorder. It is one of the most frequent autosomal dominant genetic diseases and affects one in 2.000 or 4.000 individuals. Half of patients with NF1 have a new mutation in the NF1 gene. Clinical manifestations are extremely variable and the diagnostic criteria are: a. six or more café au lait macules larger than 5mm in the greatest diameter in prepubertal and larger than 1.5cm in postpubertal children; b. two or more neurofibromas of any type or one plexiform neurofibroma; c. multiple axillary or inguinal freckles; d. sphenoid dysplasia or thinning of long bone cortex, with or without pseudoarthrosis; e. optic glioma; f. two or more iris hamartomas (Lisch nodules); g. a first-degree relative with NF1, diagnosed by the criteria above. Seizures, learning disabilities and discrete mental retardation are frequent in these patients. NF1 is a progressive disorder that may worsen with increasing age.

Neurofibromatosis: reporte de un caso y revisión bibliográfica / Neurofibromatosis: report of a case and bibliographic review

Las neurofibromatosis, son trastornos de origen genético del sistema nervioso, que afectan al desarrollo y crecimiento de los tejidos de las células neurales; estos trastornos ocasionan tumores que crecen en los nervios y producen otras anormalidades tales como cambios en la piel y deformidades en los huesos, entre otros. Esta patología ocurre en ambos sexos, en todas las razas y grupos étnicos; se las ha clasificado en tipo I y II, aunque existen otros tipos o variantes, pero no están claramente definidas. Presentamos el caso de un paciente sexo masculino, 44 años, que acude para un examen médico preocupacional, y presenta tumoraciones diseminadas, de aspecto nodular, además de manchas color “marrón claro” igualmente diseminadas y deformidad en la columna vertebral; luego del examen físico y placas de rayos X de región dorso-lumbo-sacra, con más de dos criterios a favor, se diagnostica clínicamente Neurofibromatosis tipo 1.

Neurofibromatosis is genetic disorders of the nervous system affecting the development and growth of the neural cells tissues. These disorders produce tumors growing in the nerves and other abnormalities such as changes in the skin and deformities in the bones among others. This pathology, happens in both sexes, in all races and ethnic groups; it has been classified in types I and II, though there are other types and variants, but they are not clearly defined. We present the case of a male patient, 44 years old that comes for a medical exam before being admitted in a new job. He presented disseminated tumors with nodular appearance and “light brown” spots also disseminated and backbone deformity. After physical examination and X-ray of dorsal, lumbar and sacral regions of the spine, with more than two criteria met we make the clinical diagnosis: Nuerofibromatosis Type I.

A Case of Neurofibromatosis Type 1 with Cortical Dysplasia

Neurofibromatosis type 1(NF1) is the most common neurocutaneous syndrome which has an autosomal dominant pattern of inheritance. The NF1 gene is located on chromosome 17q11.2 and encodes for neurofibromin known as tumor suppressor protein. The disorder affects almost every organ and shows neurologic manifestations such as tumors, mental retardation and epilepsy. Epilepsy associated with NF1 occurs in about 4% and is known to have relatively good prognosis. Malformations of cortical development are less common in patients with NF1 than in other phakomatoses. To our knowledge, no report on NF1 with cortical dysplasia has been published in Korea. We report a child with NF1 associated with extensive cortical dysplasia, who presented initially infantile spasms and in the following months developed tonic seizures.