Congenital bilateral absence of vas deferens

Congenital bilateral absence of the vas deferens (CBAVD) is a condition in which both vas deferens (the tubes that carry sperm from the testes to the urethra) fail to develop properly before birth. This results in obstructive azoospermia — meaning sperm are produced in the testes but cannot reach the ejaculate — making CBAVD one of the most common identifiable causes of male infertility. The condition primarily affects the male reproductive system, though the testes themselves typically function normally, producing both sperm and testosterone. Men with CBAVD usually have normal sexual development and function but are diagnosed during evaluation for infertility. Semen analysis characteristically shows low volume, acidic pH, and absence of sperm. CBAVD is strongly associated with mutations in the CFTR gene (cystic fibrosis transmembrane conductance regulator), the same gene responsible for cystic fibrosis (CF). Approximately 80% of men with CBAVD carry at least one CFTR mutation, and many carry two mutations — often one severe CF-causing mutation and one mild mutation (such as the 5T allele in intron 8). Some men with CBAVD may have mild or subclinical features of cystic fibrosis, such as mild respiratory or sinus symptoms, while others have no other CF-related manifestations. Renal anomalies, including unilateral renal agenesis, may be present in a subset of patients, particularly those without identifiable CFTR mutations. While there is no treatment to restore the vas deferens, men with CBAVD can father biological children through assisted reproductive technologies. Sperm can be retrieved directly from the testes or epididymis using techniques such as microsurgical epididymal sperm aspiration (MESA) or testicular sperm extraction (TESE), followed by intracytoplasmic sperm injection (ICSI) as part of in vitro fertilization (IVF). Genetic counseling is strongly recommended for affected men and their partners, as there is a risk of having children with cystic fibrosis if the female partner also carries a CFTR mutation.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Common questions about Congenital bilateral absence of vas deferens