The hip and knee joints are most frequently affected. Can present similar to bilateral Perthes' disease. Must also be differentiated from hypothyroidism, spondyloepiphyseal dysplasia and pseudoachondroplastic dysplasia. Ribbing form, milder, with flat epiphyses and minimal involvement of the hands and feet. Fairbank form, more severe form, with late appearing epiphyses and greater involvement of the hands and feet.
Patients have normal intelligence.
Adult height usually range from 145 to170cm. Limb epiphyses show delayed appearing centers of ossification, often demonstrating a fragmented appearence. Joint involvement is usually symmetric. Premature arthrosis of weight-bearing joints, most frequently the hips, due to delay in ossification of the capital femoral epiphysis. The cartilaginous femoral head model becomes misshapen and incongruous with time, leading to early arthritis.