Trisomy 8: an international study of 70 patients.

The Warkany syndrome is characterized by mental retardation, relatively specific facies, absent or dysplastic patellas, joint contractures, plantar/palmar furrows, distinctively abnormal toe posture, vertebral anomalies, narrow pelvis, ureteral-renal anomalies, or other abnormalities. There is no association with advanced parental age, and birthweight and length are usually commensurate with gestational age. The chromosomal mechanisms accounting for the WS include either literal trisomy (8 (aneuploidy), usually if not always with mosaicism, or translocation leading to partial trisomy 8 (8q2). In addition, some patients with mosaic trisomy 8 may not have the Warkany syndrome.