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.
Asian Continental Ancestry Group ; Genes, Neurofibromatosis 1 ; Humans ; Mutation ; Neurofibromatosis 1 ; genetics ; Neurofibromin 1 ; genetics ; Pedigree

OBJECTIVETo detect NF1 gene mutation in a patient with neurofibromatosis type 1.

METHODSFive 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.

RESULTSThe 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 .

CONCLUSIONIt 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.

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.
Child ; Genes, Neurofibromatosis 1 ; Genomics ; High-Throughput Nucleotide Sequencing ; Humans ; Mutation ; Neurofibromatosis 1/genetics*

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.
Breast ; Breast Neoplasms* ; Codon, Nonsense ; Female ; Genes, BRCA1 ; Genes, Neurofibromatosis 1 ; Germ-Line Mutation* ; Humans ; Mortality ; Neurofibromatosis 1* ; Neurofibromin 1

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.
Cafe-au-Lait Spots ; diagnosis ; genetics ; Child ; Genes, Neurofibromatosis 1 ; Growth Hormone ; deficiency ; Humans ; Male ; Mutation ; Neurofibromatosis 1 ; blood ; diagnosis

OBJECTIVE: To explore the genetic basis for a child with café-au-lait macules and juvenile xanthogranuloma. METHODS: Clinical data and peripheral blood samples of the patient and her family members were collected and subjected to targeted capture and high-throughput sequencing. Candidate variant was verified by Sanger sequencing. RESULTS: A deletional variant in exon 23 of the NF1 gene was detected in the proband. Sanger sequencing has verified it as a de novo variant, which was highly correlated with the clinical manifestations of the patient and her mother. The diagnosis of neurofibromatosis 1 (NF1) was established. The variant was unreported previously. CONCLUSION Targeted capture and next-generation sequencing combined with Sanger sequencing can facilitate early diagnosis of NF1 and provide a basis for the clinical treatment, genetic counseling and prenatal diagnosis.
Child ; Female ; Humans ; Cafe-au-Lait Spots/genetics* ; Genes, Neurofibromatosis 1 ; Neurofibromatosis 1/genetics* ; Xanthogranuloma, Juvenile/genetics*

OBJECTIVE: To explore the types of NF1 gene variants and clinical characteristics among patients with Neurofibromatosis type I (NF1). METHODS: Clinical data of 12 patients diagnosed at Ningbo Women and Children's Hospital between December 2019 and May 2022 were retrospectively analyzed. The probands and their family members were subjected to high-throughput sequencing, and candidate variants were verified by Sanger sequencing and chromosome microarray analysis. RESULTS: The 12 patients had ranged from 4 months to 27 years old, with a male-to-female ratio of 2 : 1. Cafè-au-lait spots were found in all patients. 83.3% of them also had axillary and/or inguinal freckling, 58.3% had neurofibromas, and 16.7% had congenital pseudarthrosis of the tibia. Five types of NF1 gene variants were identified in the patients, including 5 nonsense variants, 4 frameshift variants, 1 missense variant, 1 splice variant, 1 large deletion involving the whole gene. Six patients were found to harbor de novo variants, 2 had inherited the variants from their parents, and 4 were not verified for their parental origin. The c.3379del (p.Thr1127Glnfs*15) and c.6628_6629del (p.Glu2210Thrfs*10) variants were unreported in literature and databases. CONCLUSION Most NF1 patients may present with Cafè-au-lait spots initially and are due to pathogenic variant of the NF1 gene. High-throughput sequencing can efficiently identify such variants among the patients and enable the definite diagnosis.
Child ; Humans ; Female ; Male ; Neurofibromatosis 1/diagnosis* ; Cafe-au-Lait Spots/diagnosis* ; Genes, Neurofibromatosis 1 ; Retrospective Studies ; Frameshift Mutation

BACKGROUND: Neurofibromatosis type 1 (NF1) is one of the most common inherited disorders and is characterized by abnormalities in multiple tissues derived from the neural crest. OBJECTIVES: We analyzed the presence of mutations of NF1 gene in unrelated 56 Korean NF-1 patients. METHODS: Mutations were detected by polymerase chain reaction, single strand conformational polymorphism analysis and direct DNA sequencing. RESULTS: We found five different kinds of mutations in the NF1 gene from 5 out of 56 unrelated Korean NF1 patients. Sequence analysis revealed a nucleotide substitution at codon 1276 of exon 22 (CGA to TGA, R1276X), 4 by insertion at codon 1270 of exon 22 (3809 ins TGGA), a base pair deletion at codon 1398 of exon 24 (4192 del G), 4 by deletion at codon 1638 of exon 28 (4914 del CTCT), and a base pair substitution at codon 1947 of exon 31 (CGA to TGA, R1947X). All of these mutations resulted in premature termination of the mutant alleles. CONCLUSION: Results showed that common consequences of NF1 mutations are introduction of a premature stop codon, and these mutant genes may encode truncated forms of neurofibromin.
Alleles ; Base Pairing ; Codon ; Codon, Nonsense ; Exons ; Genes, Neurofibromatosis 1* ; Humans ; Neural Crest ; Neurofibromatoses* ; Neurofibromatosis 1* ; Neurofibromin 1 ; Polymerase Chain Reaction ; Sequence Analysis ; Sequence Analysis, DNA

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.
Adolescent ; Child* ; Exons ; Genes, Neurofibromatosis 1 ; Hamartoma* ; Histiocytoma, Benign Fibrous ; Humans ; Hypothalamic Diseases ; Neurocutaneous Syndromes ; Neurofibroma ; Neurofibromatoses* ; Neurofibromatosis 1* ; Neurofibromin 1 ; Puberty ; Puberty, Precocious* ; Sequence Deletion

Multiple neurofibromatosis is known to be a genetic disease with the autosomal dominant inheritance pattern. In clinical practice, however, we can hardly ever find a case in which the autosomal dominant inheritance is demonstrable, because sporadic mutation is believed to cause about 50 % of the observed rnultiple neurofibromatosis cases, and because such patients show reduced fertility. The authors observed a family case in which the typical autosomal dominant inheritance could be demonstrated. Among 17 consanguinities of the 3 generations studied, 12 had developed multiple neurofibrornatosis. The presumed reason for the high incidence of the disease in the family studied is 2 fold: 1) The autosomal dominant gene responsible for the disease is highly penetrable. 2) The mutant gene responsible for the disease, for some unexplained reason, was transmitted from patient No. 1 to a.ll of her offsprings, instead of to only half of her offsprings, as would be expected. Multiple neurofibromatosis is known to be a genetic disease with the autosomal dominant inheritance pattern. In clinical practice, however, we can hardly ever find a case in which the autosomal dominant inheritance is demonstrable, because sporadic mutation is believed to cause about 50 % of the observed rnultiple neurofibromatosis cases, and because such patients show reduced fertility. The authors observed a family case in which the typical autosomal dominant inheritance could be demonstrated. Among 17 consanguinities of the 3 generations studied, 12 had developed multiple neurofibrornatosis. The presumed reason for the high incidence of the disease in the family studied is 2 fold: 1) The autosomal dominant gene responsible for the disease is highly penetrable. 2) The mutant gene responsible for the disease, for some unexplained reason, was transmitted from patient No. 1 to a.ll of her offsprings, instead of to only half of her offsprings, as would be expected. Multiple neurofibromatosis is known to be a genetic disease with the autosomal dominant inheritance pattern. In clinical practice, however, we can hardly ever find a case in which the autosomal dominant inheritance is demonstrable, because sporadic mutation is believed to cause about 50 % of the observed rnultiple neurofibromatosis cases, and because such patients show reduced fertility. The authors observed a family case in which the typical autosomal dominant inheritance could be demonstrated. Among 17 consanguinities of the 3 generations studied, 12 had developed multiple neurofibrornatosis. The presumed reason for the high incidence of the disease in the family studied is 2 fold: 1) The autosomal dominant gene responsible for the disease is highly penetrable. 2) The mutant gene responsible for the disease, for some unexplained reason, was transmitted from patient No. 1 to a.ll of her offsprings, instead of to only half of her offsprings, as would be expected.
Consanguinity ; Family Characteristics ; Fertility ; Genes, Dominant ; Humans ; Incidence ; Inheritance Patterns ; Neurofibromatoses* ; Neurofibromatosis 1 ; Wills