Figure 8.

DSD and fetal-onset male hypogonadism. 46,XY DSD may result from various forms of primary fetal-onset male hypogonadism, or from defects in hormone action in target organs (AIS: androgen insensitivity syndrome, or 5α-reductase deficiency), without hypogonadism. In 46,XX individuals with testicular differentiation, partial virilization results from impaired testicular function; in completely virilized newborns, Leydig and Sertoli cell function is preserved and only germ cell development is impaired; however, the most frequent situation of XX virilization results from dysfunction of the adrenals (e.g., congenital adrenal hyperplasia, CAH) or the placenta (aromatase deficiency). Chromosomal DSD with 45,X/46,XY or 46,XX/46,XY karyotypes, testicular tissue is characterized by impaired function of all cell populations, as shown by the existence of testosterone and AMH levels that are below the male range. AIS, androgen insensitivity syndrome; CAH, congenital adrenal hyperplasia; Def., deficiency; Malformative, anatomical malformation of the genitalia not due to hormonal disorders; PMDS, persistent Müllerian duct syndrome, due to specific AMH defects, < or > female or male: below or above normal female or male range.