A chromosomal disorder characterized by MENTAL RETARDATION, broad thumbs, webbing of fingers and toes, beaked nose, short upper lip, pouting lower lip, agenesis of corpus callosum, large foramen magnum, keloid formation, pulmonary stenosis, vertebral anomalies, chest wall anomalies, sleep apnea, and megacolon. The disease has an autosomal dominant pattern of inheritance and is associated with deletions of the short arm of chromosome 16 (16p13.3).
