Prevalence of Congenital Bilateral Absence of the Vas Deferens
CBAVD occurs in approximately 1-2% of all infertile men and accounts for 6% of obstructive azoospermia cases. 1, 2, 3
Population-Specific Prevalence Data
In the general male population, the prevalence of congenital absence of the vas deferens (including both bilateral and unilateral forms) is approximately 0.1%, though this figure is likely underestimated because unilateral forms in asymptomatic fertile men typically go undiagnosed. 4
Among men with cystic fibrosis, CBAVD is present in nearly 95% of cases, making it the most sensitive indicator of biallelic CFTR gene abnormalities. 1, 2
In males of northern European heritage, the incidence of clinical CF (which includes CBAVD) is 1:2,000, with an equal frequency of men presenting with isolated CBAVD without significant respiratory or pancreatic disease. 1
Clinical Context and Diagnostic Considerations
CBAVD presents with characteristic semen findings: low volume ejaculate, acidic pH (<7.0), and azoospermia, which can be diagnosed definitively by physical examination demonstrating bilateral absence of the vasa deferentia. 1, 5
The vast majority of CBAVD patients (78%) carry at least one CFTR mutation, with 46% having two identifiable mutations and 28% having only one mutation detected on standard testing. 1
ADGRG2 gene mutations account for approximately 2% of CBAVD cases, representing the second most common genetic cause after CFTR mutations, and these cases present as X-linked familial infertility. 4, 6
Between 10-20% of CBAVD cases remain without a genetic diagnosis despite comprehensive CFTR and ADGRG2 testing, and many of these unexplained cases are associated with unilateral renal agenesis (occurring in 10% of bilateral vasal agenesis cases), suggesting an early Wolffian duct developmental disorder. 1, 4
Important Clinical Caveats
Congenital unilateral absence of the vas deferens (CUAVD) is more common than bilateral absence but often goes undiagnosed because 60.3% of these men are non-azoospermic (either oligozoospermic or normozoospermic), and 42% of non-azoospermic CUAVD men have achieved natural pregnancy. 7
CUAVD is associated with ipsilateral renal anomalies in 26-75% of cases, compared to only 10% in bilateral vasal agenesis, making abdominal imaging essential regardless of CFTR status. 1
The reported prevalence of 0.1% in the general population significantly underestimates true prevalence because it excludes asymptomatic fertile men with unilateral forms who never undergo evaluation. 4