The genetic basis of congenital bilateral absence of the vas deferens and cystic fibrosis.

Congenital bilateral absence of the vas deferens (CBAVD) has long been thought to be a rare and distinct clinical and genetic entity. However, it occurs in 1-2% of the infertile male population (Jequier et al, 1985). Recently, this disorder has been shown to represent a mild (reproductive) form of cystic fibrosis (CF) (Anguiano et al, 1992). This finding mandates that proper genetic counseling take place for patient, spouse, and appropriate family members. With the advent of techniques such as microscopic epididymal sperm aspiration (MESA) or Moni’s Window, pregnancies have been achieved in couples where the male partner is afflicted with CBAVD. What was once a brief and frustrating conversation between patient and urologist has now been markedly expanded to include a discussion on the hopeful possibilities of fatherhood but also on the myriad of other concerns that the diagnosis of potential CF raises. Complete bilateral absence of the scrotal vasa is the hallmark of CBAVD. For the purposes of this discussion, CBAVD will be defined in a strict sense because some of the partial forms of vasal agenesis, such as unilateral vasal agenesis, may not have the same genetic or pathophysiological basis as does classic CBAVD in otherwise healthy men. Therefore, CBAVD will be defined as occurring only when both scrotal vasa are deficient to palpation and/or exploration, either partially or totally. If either vasa is palpable from its origin to the external ring, CBAVD is not present. By adherence to this definition, we can segregate various types of vasal agenesis into different clinical Minireview