CFTR gene mutations in Japanese individuals with congenital bilateral absence of the vas deferens.

Congenital bilateral absence of the vas deferens (CBAVD) is a monosymptomatic disease confined to the male reproductive system with similarity to the phenotype of cystic fibrosis (CF), and mutations in the CFTR gene are highly prevalent in Caucasian CBAVD patients. While CF is very rare in Japan, CBAVD is not. Our previous study demonstrated high prevalence of the 5T allele in the CFTR gene in Japanese CBAVD patients. We analyzed whole exons of the CFTR gene in 19 CBAVD patients and 53 normal individuals using polymerase chain reaction amplification-single strand conformation polymorphism analysis and direct sequencing. Three missense mutations (W216X, G1349S, Q1352H) were found in seven CFTR alleles, and the 5T allele was positive in 11 of 38 CFTR patient alleles. Consequently, 47% of CFTR chromosomes in the patients were affected, and 11 individuals (58%) had at least one mutated CFTR allele. In contrast, three of 53 normal individuals (5.7%) had a missense mutation in one of the CFTR genes, but no 5T allele was detected (both P<0.0001). Mutations of the CFTR gene are closely associated with Japanese patients with CBAVD.