[Agenesis of the vas deferens in male infertility. A tentative classification based on 39 cases]

We attempted to establish a classification of vas deferens agenesia observed in male infertility to better ascertain the pathophysiology involved and help guide genetic counselling.

Among 387 men consulting for infertility, agenesia of the vas deferens was confirmed by transrectal ultrasonography in 39. A search for 13 different cystic fibrosis mutations was performed in subjects without associated renal agenesia.

Among the 39 cases, we identified 4 ultrasonographic categories: unique bilateral agenesia (25 cases), bilateral agenesia associated with renal agenesia (1 case), unique unilateral agenesia (6 cases) and unilateral agenesia with renal agenesia (7 cases). Presence or absence of a seminal vesicle was variable. A cystic fibrosis mutation was observed in 64% of the bilateral cases and in none of the unilateral cases. The delta F 508 mutation accounted for 62% of the mutations. Phenotypically, there was not distinction between patients with and without a mutation. In cases of unilateral agenesia of the vas deferens, azoospermia was more frequent in unique forms than in forms with associated renal agenesia.

Presence or absence of a mutation does not affect the pathophysiology of vas deferens agenesia in cases without associated renal agenesia. Genetic counselling should however take into account the presence of an associated mutation. Vas deferens agenesia associated with renal agenesia is not associated with cystic fibrosis mutations and results from a different pathogenic mechanism.