Cystic fibrosis transmembrane conductance regulator mutations and polymorphisms associated with congenital bilateral absence of vas deferens in a restricted group of patients from North Africa

Background: Congenital bilateral absence of vas deferens (CBAVD) is responsible for 2-6% of male infertility. It occurs in 95% of men with cystic fibrosis. This malformation is present in patients with a sterile obstructive azoospermia but without clinical evidence of cystic fibrosis. Molecular study of the cystic fibrosis transmembrane conductance regulator (CFTR) gene responsible for cystic fibrosis could show the relationship between this disease and bilateral absence of vas deferens. Patients and methods: The study involved 20 male patients aged between 28-40 years, referred with suspected cystic fibrosis and in whom bilateral absence of vas deferens was confirmed by cyto-biochemical analyses and urogenital ultrasound. Molecular study of the CFTR gene was based on several techniques: DHPLC, DGGE and direct sequencing. Results: Thirteen patients had CFTR mutations: F508del, G542X, W1282X, E1104X, 711 + 1G -> T, V201M (TG) m and IVS8-5T. These mutations were associated with polymorphisms: M470V and D1270N. Seven cases presented only polymorphisms. Conclusion: The different mutations found in this study were associated with polymorphisms which decrease the severity of the disease and delay its onset. Thus, bilateral agenesis of the vas deferens is classed as a form of cystic fibrosis with only genital expression.