Analysis of NF1 gene mutations in neurofibromatosis type 1 patients in Japan.

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. Here, we report two novel deletion mutations of the NF1 gene from two out of 25 unrelated Japanese NF1 patients. These mutations were detected using polymerase chain reaction (PCR)/single-strand conformation polymorphism (SSCP) analysis. Sequencing analysis revealed a 4 base pair (bp) deletion at 5679 (5679delACTG) in exon 30 in one patient and a single bp deletion at 5949 (5949delA) in exon 32 in the other patient. Both of these mutations resulted in frameshifts, followed by premature terminations of the mutant allele. Because only a few large rearrangements of the NF1 gene have been reported in NF1 patients, it is likely that subtle mutations such as these are common.