Dysgerminoma, gonadoblastoma, and testicular germ cell neoplasia in phenotypically female and male siblings with 46 XY genotype.

46 XY gonadal dysgenesis is a syndrome characterized by a female phenotype with streak gonads and complicated by the frequent occurrence of germ cell tumors. The syndrome and the risk of malignant disease occur in female siblings sharing the XY genotype, and screening of female siblings and prophylactic gonadectomy in those affected is generally recommended. A family of four siblings is described in which two phenotypically female XY children and one male each have developed germ cell tumors, demonstrating that brothers of affected sisters may also be at risk.