Chromosome studies of males in an institution for the mentally handicapped.

Abstract
Karyotypes were examined in 512 (91 .cntdot. 9%) of 557 male patients in an institution for the mentally handicapped. A total of 110 (21 .cntdot. 5%) had an abnormal karyotype: 65 (12 .cntdot. 7%) with Down''s syndrome, 30 (5 .cntdot. 9%) with the fragile X syndrome, 13 (2 .cntdot. 5%) with autosomal anomalies other than Down''s syndrome (12 unbalanced, one balanced), and two (0 .cntdot. 4%) with sex chromosome anomalies.