In 3beta-HSD deficiency, male infants are undervirilized whereas female infants are virilized. Inadequate concentrations of dihydrotestosterone within the genital tubercle and labioscrotal folds lead to only partial masculinization of the external genitalia. Later androgen exposure fails to correct any defect during this period. This condition is also referred to as pseudovaginal perineoscrotal hypospadias because of the specific anatomical ambiguity most often observed. However, the sperm carrying ducts end blindly before the prostate gland, so even if spermatogenesis occurs, the ejaculate is azoospermic.
Inheritance is autosomal recessive and is common among some ethnic groups due to consanguinity.
In the undiagnosed subject or those in whom orchiectomy is not accomplished by the age of puberty, the ambiguous genitalia become further virilized with phallic growth and development of a muscular male habitus and male body hair patterns. Stimulation with human chorionic gonadotropin further accentuates this altered ratio. Inguinal or labial testes may be palpable, although they may only be discovered during exploration of an apparent inguinal hernia. The vagina is short due to secretion of MIS by testicular Sertoli cells. Increased testicular stimulation by elevated gonadotropins at puberty results in normal or elevated testosterone levels to which the subject is nonresponsive.