What is congenital absence of the vas deferens (CAVD)?
Congenital absence of the vas deferens (CAVD) is a rare genetic problem that causes infertility in about one in 2500 men. Many men with CAVD have a genetic change (mutation) in the cystic fibrosis gene (cystic fibrosis transmembrane regulator, CFTR) which is the gene responsible for transportation of material across the lining of many surfaces of the body. Several parts of the reproductive tract (including the vas deferens) are missing from birth in men born with CAVD. This stops sperm from the testes passing out into the ejaculate. In most men with cystic fibrosis, the vas deferens is absent.