A newborn infant with ambiguous genitalia is found to have a 46, XX karyotype All of the following are diagnostic possibilities Except

Infants with partial androgen resistance may have ambiguous genitalia, but the karyotype. is 46,XY. These infants have testes and high levels of testosterone, which are incompletely effective in Virilizing the external genitalia in a normal male pattern. The defect is at the level of the androgen receptor. Female infants with congenital adrenal hyperplasia due to 21-hydroxylase deficiency may exhibit a variable degree of masculinization of the external genitalia because of prenatal exposure to high levels of circulating adrenal androgens' Most infants with true hermaphroditism have a 46,XX karyotype. However, gonadal tissue includes both ovarian and testicular elements. The testicular androgens cause external virilization, leading to ambiguous genitalia. In a similar fashion, a maternal Virilizing tumor may expose a female fetus to high levels of androgen.