The cystic fibrosis transmembrane regulator gene and male infertility

Congenital bilateral absence of the vas deferens (CBAVD) is a relatively frequent cause of male infertility accounting for 1-2% of cases of male sterility and at least 6% of cases of obstructive azoospermia. In the last decade a genetic basis for CBAVD has been provided by its association with cystic fibrosis (CF) and nowadays CBAVD is in most cases considered to be a mild or incomplete form of CF disease. Many individuals with CBAVD show usually mild CF-compatible clinical manifestations, but the long-term prognosis could possibly not be as innocuous as it presently looks: more data will be available through medium or long-term follow-up studies. Once a correct diagnosis of CBAVD has been formulated and if the couple is planning a pregnancy by artificial reproductive technology, it is crucial to test both the affected male and his partner for CFTR mutations. Such testing has a number of complex implications and should always be performed together with genetic counselling. Other issues are debated in this article including CF mutations in non-CBAVD forms of male infertility, and the potentially misleading role of CF genetic analysis when used to rule out other possible causes of infertility in azoospermic men. (C) 2000, Editrice Kurtis.