[Molecular basis of cystic fibrosis and congenital bilateral agenesis of vas deferens].

Cystic fibrosis (CF) is the most common severe autosomal recessive disorder of the Caucasian population. Since the identification of the CFTR (Cystic Fibrosis Transmembrane Conductance Regulator) gene in 1989, over 550 mutations have been characterized. CFTR can function as a chloride channel with unique properties. It has become clear, however, that CFTR can also regulate a variety of other cationic and anionic channels. The CFTR gene screening in men with bilateral congenital absence of the vas deferens (CBAVD) led to speculation that these patients have a specific mild form of CF. Recent studies allow patients with CBAVD to be classified in four categories: patients with two CFTR mutations (19%); patients with one CFTR mutation and the 5T allele in trans (33%); patients with only one CFTR mutation or only the 5T allele (27%); patients without CFTR mutations and 5T allele (21% The high proportion of patients with CBAVD who do not have CFTR mutations allows to suggest two hypothesis : other undetected changes in CFTR may be involved in CBAVD ; another gene or genes could be responsible for CBAVD.