Rare sex chromosome aneuploidies: 49,XXXXY and 48,XXXY syndromes.

49,XXXXY and 48,XXXY syndromes are rare gonosomal aneuploidies in which the affected individuals present with characteristic facial and skeletal malformations, intrauterine growth retardation, and psychomotor retardation. Psychological, endocrinologic and orthopedic disorders constitute the major problems in the clinical follow-up. Sex chromosome abnormalities should especially be kept in mind in the evaluation of patients with micropenis, mental retardation and accompanying behavioral disturbances. Management mandates a multidisciplinary approach with pediatric endocrinology, pediatric surgery, orthopedics, psychiatry, and clinical genetic evaluations.