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 sperm, which are immotile due to the absence of vas deferens.
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.
