How the Diagnosis is Made

The diagnosis of SED is made on the basis of clinical features and relevant x-rays. Radiographic features that are particularly characteristic are the biconvex appearance of the ossification center of the vertebral bodies on lateral radiographs of the spine and the several-year delay in the ossification of the iliopubic ramus and epiphyses of the long bones, particularly the femoral heads. Moreover, SED-congenita may be suspected in the prenatal period on the basis of ultrasonography. The gene is known, but testing may be difficult considering its size. Certain mutations of the gene have been associated with different forms of SED.