Anomalies of hands, face, upper spine, and joint articulations (e.g., dislocations of hip, knee, and elbow). Characteristic facial features are prominent forehead, widened eyes, and hypoplastic nasal bridge. Spina bifida, clubfoot, platybasia, kyphosis and lordosis, mild mental retardation, and dwarfism also occur. Both autosomal dominant and recessive forms exist.