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

Cardiovascular System/pathology* ; Constriction, Pathologic/genetics* ; Point Mutation ; Neurofibromin 1/genetics* ; Animals ; Mice

OBJECTIVETo report on two children manifesting multiple cafe-au-lait spots suspected as neurofibromatosis type 1, and perform NF1 gene mutation analysis.

METHODSBlood samples were collected from the 2 children, their unaffected parents and 100 normal controls. The entire coding region of the NF1 gene was amplified by PCR and subjected to direct sequencing.

RESULTSIn patient 1, a novel frameshift mutation c.1948delT (p.Leu650TyrfsX38) was identified in exon 12 of the NF1 gene. And in patient 2, a previously reported nonsense mutation c.541C>T (p.Gln181X) was revealed in exon 4b. The same mutations were not detected in their unaffected parents or 100 normal controls.

CONCLUSIONThe two patients were diagnosed with neurofibromatosis type 1 by molecular genetic testing. The pathogenic mutations were c.1948delT and c.541C>T, respectively.

Adult ; Base Sequence ; Exons ; Female ; Humans ; Infant ; Male ; Molecular Sequence Data ; Neurofibromatosis 1 ; genetics ; Neurofibromin 1 ; genetics ; Point Mutation

Ependymomas occur in both the brain and spine. The prognosis of these tumors sometimes differs for different locations. The genetic landscape of ependymoma is very heterogeneous despite the similarity of histopathologic findings. In this review, we describe the genetic differences between spinal ependymomas and their intracranial counterparts to better understand their prognosis. From the literature review, many studies have reported that spinal cord ependymoma might be associated with NF2 mutation, NEFL overexpression, Merlin loss, and 9q gain. In myxopapillary ependymoma, NEFL and HOXB13 overexpression were reported to be associated. Prior studies have identified HIC-1 methylation, 4.1B deletion, and 4.1R loss as common features in intracranial ependymoma. Supratentorial ependymoma is usually characterized by NOTCH-1 mutation and p75 expression. TNC mutation, no hypermethylation of RASSF1A, and GFAP/NeuN expression may be diagnostic clues of posterior fossa ependymoma. Although MEN1, TP53, and PTEN mutations are rarely reported in ependymoma, they may be related to a poor prognosis, such as recurrence or metastasis. Spinal ependymoma has been found to be quite different from intracranial ependymoma in genetic studies, and the favorable prognosis in spinal ependymoma may be the result of the genetic differences. A more detailed understanding of these various genetic aberrations may enable the identification of more specific prognostic markers as well as the development of customized targeted therapies.
Brain ; Ependymoma* ; Genetic Research* ; Genetics ; Methylation ; Multiple Endocrine Neoplasia Type 1 ; Neoplasm Metastasis ; Neurofibromin 2 ; Prognosis ; Recurrence ; Spinal Cord ; Spine

Neurofibromatosis type 1 (NF1) is a common autosomal dominant disease characterized by formation of multiple benign and malignant tumors. People with this disorder also experience chronic pain, which can be disabling. Neurofibromin, the protein product of the Nf1 gene, is a guanosine triphosphatase activating protein (GAP) for p21Ras (Ras). Loss of Nf1 results in an increase in activity of the Ras transduction cascade. Because of the growing evidence suggesting involvement of downstream components of the Ras transduction cascade in the sensitization of nociceptive sensory neurons, we examined the stimulus-evoked release of the neuropeptides, substance P (SP) and calcitonin gene-related peptide (CGRP), from primary sensory neurons of mice with a mutation of the Nf1 gene (Nf1+/-). Measuring the levels of SP and CGRP by radioimmunoassay, we demonstrated that capsaicin-stimulated release of neuropeptides is 3-5 folds higher in spinal cord slices from Nf1+/- mice than that from wildtype mouse tissue. In addition, the potassium- and capsaicin-stimulated release of CGRP from the culture of sensory neurons isolated from Nf1+/- mice was more than double that from the culture of wildtype neurons. Using patch-clamp electrophysiological techniques, we also examined the excitability of capsaicin-sensitive sensory neurons. It was found that the number of action potentials generated by the neurons from Nf1+/- mice, responding to a ramp of depolarizing current, was more than three times of that generated by wildtype neurons. Consistent with that observation, neurons from Nf1+/- mice had lower firing thresholds, lower rheobase currents and shorter firing latencies compared with wildtype neurons. These data clearly demonstrate that GAPs, such as neurofibromin, can alter the excitability of nociceptive sensory neurons. The augmented response of sensory neurons with altered Ras signaling may explain the abnormal pain sensations experienced by people with NF1 and suggests an important role of GAPs in the mechanism of sensory neuron sensitization.
Action Potentials ; Animals ; Calcitonin Gene-Related Peptide ; Capsaicin ; Mice ; Mutation ; Neurofibromatosis 1 ; genetics ; physiopathology ; Neurofibromin 1 ; genetics ; metabolism ; Nociceptors ; cytology ; Pain ; physiopathology ; Patch-Clamp Techniques ; Signal Transduction

OBJECTIVETo identify the genetic etiology in a Chinese patient with neurofibromatosis type 1 (NF-1).

METHODSAll coding exons and the flanking sequences of neurofibromin 1 (NF1) gene from the patient were captured, individually barcoded and subjected to HiSeq2000 high-throughput sequencing. Suspected mutation was validated in the nuclear family members with Sanger sequencing.

RESULTSA novel indel mutation, c.789_790delAGinsT, was identified in the exon 8 of the NF1 gene in the patient but not in her asymptomatic parents. The mutation was predicted to have caused shifting of the reading frame and a premature downstream stop codon (p.K263Nfs*18). Two known polymorphisms, c.888+108 C>T (rs2953000) and c.888+118 G>T (rs2952999), was detected in the flanking of the indel mutation in the patient and her father. Sequencing chromatogram for the family indicates that above changes are located on the same chromosome.

CONCLUSIONThe c.789_790delAGinsT, as a de novo mutation occurring on the paternally derived chromosome, is most likely to be causative for the disease. Compared with Sanger sequencing, targeted next-generation sequencing is more efficient and can dramatically reduce the cost for the genetic testing of NF-1.

Adult ; Amino Acid Sequence ; Base Sequence ; Female ; Humans ; Molecular Sequence Data ; Neurofibromatosis 1 ; enzymology ; genetics ; Neurofibromin 1 ; genetics ; metabolism ; Point Mutation

Neurofibromatosis type 1 (NF1) is one of the most common autosomal dominant disorders in humans. NF1 is caused by mutations in the NF1 gene which consists of 57 exons and encodes a GTPase activating protein (GAP), neurofibromin. To date, more than 640 different NF1 mutations have been identified and registered in the Human Gene Mutation Database (HGMD). In order to assess the NF1 mutational spectrum in Korean NF1 patients, we screened 23 unrelated Korean NF1 patients for mutations in the coding region and splice sites of the NF1 gene. We have identified 21 distinct NF1 mutations in 22 patients. The mutations included 10 single base substitutions (3 missense and 7 nonsense), 10 splice site mutations, and 1 single base deletion. Eight mutations have been previously identified and thirteen mutations were novel. The mutations are evenly distributed across exon 3 through intron 47 of the NF1 gene and no mutational hot spots were found. This analysis revealed a wide spectrum of NF1 mutations in Korean patients. A genotype- phenotype correlation analysis suggests that there is no clear relationship between specific NF1 mutations and clinical features of the disease.
Adolescent ; Adult ; Child ; Child, Preschool ; DNA/chemistry/genetics ; DNA Mutational Analysis ; Genotype ; Humans ; Infant ; Korea ; Middle Aged ; *Mutation ; Neurofibromatosis 1/*genetics/pathology ; Neurofibromin 1/*genetics ; Phenotype ; Research Support, Non-U.S. Gov't