The vas deferens is a tube-like structure in the male reproductive system that connects the epididymis, the site of storage of sperm, to the urethra, the tube that expels the sperm. Congenital absence of the vas deferens (CAVD) is a condition where the vas deferens fails to develop normally, resulting in defects in the absence of transport of the sperm to the urethra. The condition can be unilateral or bilateral; in the latter case, leading to azoospermia and infertility. From 65-90% of patients affected by this condition are carriers of cystic fibrosis, and mutations in the CFTR gene in these patients are actually causal of CBAVD. In fact, CBAVD is one of the most consistent features of CF. In most patients with CAVD, the body and tail of the epididymis also may be absent; however, the head is invariably present. Spermatogenesis is usually normal, even though sperms cannot be detected in the semen.
About 2% of men with infertility are supposed to suffer from CBAVD. Semen in affected individuals contains little or no sperms, and is usually acidic and low in volume. Since spermatogenesis is normal, infertility can be treated in such patients with the use of techniques like microsurgical epididymal sperm aspiration (MESA) and intracytoplasmic sperm injection (ICSI). However, considering the risk of having progenies affected with CF, it is important before such a procedure to undergo genetic counseling and preferably to get the carrier status of the female partner checked out.
Lissens et al. (1999) analyzed 20 CBAVD males from Egypt for the presence of 12 common Caucasian CFTR mutations and the intron 8 5T splice variant, IVS-5T, known to be a major cause of CBAVD in Caucasian patients.
Hussein et al. (2011) studied 30 patients with CBAVD and 30 fertile controls to assess the prevalence of ?-F508 mutation and 5T allele in a sample of Egyptian patients having congenital bilateral absent vas deferens (CBAVD).
Samilchuk (2005) carried out DNA diagnosis of single gene disorders in Kuwait, and detected mutations in the CFTR gene in patients with CBAVD.