CFTR Gene Mutations
Mutations in the cystic fibrosis trans membrane conductance regulator gene cause congenital bilateral absence of the vas deferens (CBAVD) in approximately 1% of the infertile males. It is a common cause of azoospermia associated with low semen volume and acidic pH. These male will have normal testicular
Approximately 80% of men with CBAVD are found to have at least one allele mutated in the CFTR gene. The most common CFTR mutation is a three base- paired deletion at position 508 that causes an in-frame deletion of a phenyloalanine. The mutant protein is known as ∆ F508 CFTR.
Congenital unilateral absence of the vas deferens (CUAVD) is a similar condition that involves aplasia of only one side of the vas deferens. It presents with infertility rarely. CFTR gene mutations have been reported in 43% of men with unilateral absence of the vas deferens.