Screening of mutations in the CFTR gene in 1195 couples entering assisted reproduction technique programs

Genetic testing of the cystic fibrosis transmembrane conductance ( CFTR) gene is currently performed in couples undergoing assisted reproduction techniques ( ART), because of the high prevalence of healthy carriers in the population and the pathogenic relationship with congenital bilateral absence of vas deferens ( CBAVD). However, discordant data have been reported concerning the usefulness of this genetic test in couples with no family history of cystic fibrosis ( CF). In this study, we report the results of CFTR molecular screening in 1195 couples entering ART. Genetic testing was initially carried out in a single partner of each couple. CFTR mutations were detected in 55 subjects ( 4.6%), a percentage that overlaps with the one reported in the general population. However, significantly higher frequencies of were found in CBAVD individuals ( 37.5%) and in males with nonobstructive azoospermia ( 6.6%). The 5T allele was found in 78 patients ( 6.5%). This figure was again significantly different in males with nonobstructive-azoospermia ( 9.9%) and in those with CBAVD ( 100%). All together, 139 subjects ( 11.6%) had either a CFTR mutation or the 5T allele. Subsequent molecular analysis of their partners disclosed a CFTR mutation or 5T allele in nine cases ( 6.5%). However, none of these couples had CFTR alterations in both members, a CFTR mutation being invariably present in one partner and the 5T allele in the other. In order to improve genetic counselling of these couples, the TG-M470V-5T association was analyzed, and a statistically significant relationship between 12TG-V470 and CBAVD was detected.