Screening for mutation site on the type I neurofibromatosis gene in a family.

Purpose: The purpose of the study was to determine the sites and types of mutations associated with type I neurofibromatosis (NF1) in the NF1 gene in a family with NF1 patients.

Methods: The blood samples obtained from this family (four patients and one normal healthy individual) were analyzed by performing polymerase chain reaction (PCR) and DNA sequencing for mutation screening.

Results: We found synonymous mutations in exons 7, 38, 50, and 56 of the NF1 gene. This implied that the third codon had a new SNP that did not lead to a change in the amino acid coding. The exon 19 mutation was CAG homozygous, while it was C/TAG heterozygous in normal individuals. The stop codon led to nonsense-codon-mediated decay of the mRNA (NMD), thus resulting in only one copy of the NF1 gene that encodes the normal protein in individuals.

Conclusions: The synonymous mutations in the NF1 gene occur in exons 7, 38, 50, and 56. The CAG homozygous mutations may occur in exon 19, and the C/TAG heterozygous mutations may occur in the others. This mutation may be responsible for NF1 in patients in this family and may warrant extensive research on the NF1 gene.