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

Objective: To investigate the clinicopathological, immunophenotypic, and genetic features of malignant peripheral nerve sheath tumor (MPNST). Methods: Twenty-three cases of MPNST were diagnosed at the Jiangsu Province Hospital (the First Affiliated Hospital of Nanjing Medical University), China, between January 2012 and December 2022 and thus included in the study. EnVision immunostaining and next-generation sequencing (NGS) were used to examine their immunophenotypical characteristics and genomic aberrations, respectively. Results: There were 10 males and 13 females, with an age range of 11 to 79 years (median 36 years), including 14 cases of neurofibromatosis type I-associated MPNST and 9 cases of sporadic MPNST. The tumors were located in extremities (7 cases), trunk (4 cases), neck and shoulder (3 cases), chest cavity (3 cases), paraspinal area (2 cases), abdominal cavity (2 cases), retroperitoneum (1 case), and pelvic cavity (1 case). Morphologically, the tumors were composed of dense spindle cells arranged in fascicles. Periphery neurofibroma-like pattern was found in 73.9% (17/23) of the cases. Under low magnification, alternating hypercellular and hypocellular areas resembled marbled appearance. Under high power, the tumor cell nuclei were irregular, presenting with oval, conical, comma-like, bullet-like or wavy contour. In 7 cases, the tumor cells demonstrated marked cytological pleomorphism and rare giant tumor cells. The mitotic figures were commonly not less than 3/10 HPF, and geographic necrosis was often noted. Immunohistochemically, tumor cells were positive for S-100 (14/23, 60.9%) and SOX10 (11/23, 47.8%). The loss of the CD34-positive fibroblastic network encountered in neurofibromas was observed in 14/17 of the MPNST cases. The loss of H3K27me3 expression was observed in 82.6% (19/23) of the cases. Moreover, SDHA and SDHB losses were presented in one case. NGS revealed that NF1 gene loss of function (germline or somatic) were found in all 5 cases tested. Furthermore, four cases accompanied with somatic mutations of SUZ12 gene and half of them had somatic mutations of TP53 gene, while one case with germline mutation in SDHA gene and somatic mutations in FAT1, BRAF, and KRAS genes. Available clinical follow-up was obtained in 19 cases and ranged from 1 to 67 months. Four patients died of the disease, all of whom had the clinical history of neurofibromatosis type Ⅰ. Conclusions: MPNST is difficult to be differentiated from a variety of spindle cell tumors due to its wide spectrum of histological morphology and complex genetic changes. H3K27me3 is a useful diagnostic marker, while the loss of CD34 positive fibroblastic network can also be a diagnostic feature of MPNST. NF1 gene inactivation mutations and complete loss of PRC2 activity are the common molecular diagnostic features, but other less commonly recurred genomic aberrations might also contribute to the MPNST pathogenesis.
Female ; Male ; Humans ; Child ; Adolescent ; Young Adult ; Adult ; Middle Aged ; Aged ; Neurofibrosarcoma ; Neurofibromatosis 1 ; Histones ; Genes, p53 ; Nerve Sheath Neoplasms

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 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*

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

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

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

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.
Female ; Gene Expression ; Genes, Neurofibromatosis 1* ; Genetic Counseling ; Genetics ; Germ-Line Mutation ; Graves Disease ; Humans ; Incidence ; Iris ; Neurofibroma ; Neurofibromatoses* ; Neurofibromatosis 1* ; Phenotype ; Siblings ; Skin ; Skin Manifestations

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

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.
Brain ; Cafe-au-Lait Spots ; Codon, Nonsense ; Diagnosis ; Female ; Genes, Neurofibromatosis 1 ; Hamartoma ; Humans ; Intellectual Disability ; Korea ; Male ; Mutation, Missense ; Nervous System ; Neurofibroma ; Neurofibroma, Plexiform ; Neurofibromatosis 1* ; Peripheral Nerves ; Retrospective Studies ; Seizures ; Skin ; Thorax