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.