Diastrophic dysplasia (DTD) is a chondrodysplasia causing severe growth retardation, and structural and functional abnormalities of joints. Growth retardation and joint abnormalities are already present in utero, and mean height at birth is 32.5 cm. Extremities are short while the trunk is of normal size, upper arms show ulnar deviation with stiff fingers and a "hitchhiker" thumb. Hips are stiff and most patients have club foot. A cleft palate is frequent. Growth remains slow, the median adult height for males is 135 cm and 129 cm for females. Changes in the joints often progress with age and corrective surgery becomes necessary.