Diagnosis of the Partial Androgen Insensitivity Syndrome During Infancy

WHEN a child is born with ambiguous genitalia, the sex of rearing becomes of preeminent importance. Androgen insensitivity must be recognized in those genetic males with borderline phallic development if appropriate assignment as females is to be made. The androgen insensitivity syndrome (AIS) may occur in the complete form (CAIS), in which no masculinization of the external genitalia occurs during fetal development and rearing clearly should be female, and the partial form (PAIS), in which varying degrees of virilization of the external genitalia occur. The latterform presents at birth with ambiguous genitalia and must be differentiated from other forms of male pseudohermaphroditism. If CAIS is diagnosed during infancy, the clinical presentation may include the presence of palpable inguinal gonads, inguinal herniae, or both.1Partial androgen insensitivity syndrome may be diagnosed in infants with ambiguous genitalia and a 46,XY genotype. The defect in CAIS may be caused by absent