Familial bilateral vas deferens agenesis

Two brothers with bilateral vas deferens agenesis are described, one of them with a chromosome mosaicism (46,XX/47,XXY). To our knowledge, there are not any previous reports of both conditions existing simultaneously. The patients consulted us because of infertility; they have normal sexual function, normal physical examination, but typical semen analyses with azoospermia, low semen volume, low pH, and negative fructose test. It appears to us that bilateral vas deferens agenesis may be genetic in origin in some patients.