[Mixed gonadal dysgenesis associated with an isodicentric Y chromosome].

Authors report a case of mixed gonadal dysgenesis with a karyotype containing an isodicentric Y chromosome in mosaic form, which was diagnosed in an infant. They emphasize the necessity of the special investigations of newborn with perineoscrotal hypospadia and bilateral or unilateral maldescent testes immediately after birth. The result of accurate evaluation provides correct sex assignment and the prevention of the neoplastic degeneration of a dysgenetic gonad.