Does it always have to be Perthes' disease? What is epiphyseal dysplasia?

The epiphyseal dysplasias are classified as osteochondral dysplasias in a heterogeneous group of skeletal dysplasias. The common feature of these hereditary conditions is short stature attributable to skeletal dysplasia at various sites. Multiple epiphyseal dysplasia and spondyloepiphyseal dysplasia are of interest to the authors, because the two syndromes are similar in their morphologic features and at first glance suggest the diagnosis of Perthes' disease. Spondyloepiphyseal dysplasia (Wiedemann-Spranger syndrome) is a disorder of growth in which there is an abnormality of enchondral ossification affecting the vertebral bodies and the epiphyses of the long bones. The two forms are the more severe congenita form (Type I), which is inherited as an autosomal dominant condition and is associated with a highly disproportional reduction in growth and severe coxa vara, and the milder tarda form which is an X-linked recessive condition, in which growth in adolescence is defective after normal childhood development. Multiple epiphyseal dysplasia is an abnormality of enchondral ossification, especially of the femoral head epiphysis, and it is an autosomal dominant condition. Depending on its severity, a distinction is made between the severe Fairbank form, the milder Ribbing form, and a mild localized Meyer form.