Different cystic fibrosis transmembrane conductance regulator mutations in Chinese men with congenital bilateral absence of vas deferens and other acquired obstructive azoospermia

Objective: To investigate cystic fibrosis transmembrane conductance regulator (CFTR) gene in Chinese men with congenital bilateral absence of vas deferens (CBAVD) and other obstructive azoospermia.

Materials and methods: Four hundred one patients with obstructive azoospermia were included. Patients were grouped as 158 with CBAVD and 243 with other acquired obstructive azoospermia. Another 200 fertile men were used as controls. Genomic deoxyribonucleic acid was isolated from peripheral blood lymphocytes for all men. The exon 10 and 11 CFTR genes were amplified and sequenced. The frequency of CFTR gene mutations was compared among 3 groups.

Results: Six heterozygous mutations (+/-), I556V, M469V, E527N, F508del, S485C, and I558S, were found in 30 patients, and 1 homozygous mutation (+/+), I556V, was found in 1 patient. The overall frequency of CFTR mutations was 31 of 401 (7.7%). Of these mutations, I556V was the most common type with 24 of 31 (77.4%). In CBAVD group, 20 of 158 patients were identified with 6 different heterozygous mutations (I556V, M469V, E527N, F508del, S485C, and I558S) and 1 homozygous mutation (I556V). The rate of CFTR mutations was 12.7%. In acquired obstructive group, 11 of 243 patients were identified with 2 different heterozygous mutations, I556V and M469V; the rate of mutations was 4.5%. No CFTR mutations were identified in controls. There was significant difference among 3 groups (P = .000). The frequency of CFTR mutations in CBAVD is 2-fold higher than in other acquired obstructive group.

Conclusion: Different CFTR mutations are observed in Chinese patients with CBAVD. I556V is the major common type of CFTR mutations in Chinese patients with CBAVD.