Molecular analysis of mutations and polymorphisms in the CFTR gene in male infertility.

Mutations of the cystic fibrosis transmembrane regulator (CFTR) gene and polymorphisms, such as the (TG)m and Tn polymorphic loci in intron 8 at the splice acceptor site of exon 9, can cause male infertility. The aim of this study was to investigate the frequency of the most prevalent cystic-fibrosis-causing mutations, the IVS8-Tn alleles and IVS8-TG12 variant in the presence of IVS8-5T in patients with altered semen parameters (group I with obstructive azoospermia, group II with secretory azoospermia and group III with severe oligozoospermia) compared with a control group with normozoospermia. CFTR mutations were found in 26.5% and 14.3% of chromosomes of patients of group I and II respectively (P < 0.001, P < 0.05). The frequency of the 5T allele was 23.5% in patients in group I (P < 0.01), and was linked exclusively with TG12 allele. The present study reports for the first time a high proportion of the 5T allele in patients in group III (9.2%, P < 0.05). These results underline the importance of performing molecular analysis of mutations and IVS8-Tn polymorphism in the CFTR gene and appropriate genetic counselling to all couples undergoing assisted reproductive technologies when the partner has azoospermia or severe oligozoospermia.