Spondyloepiphyseal dysplasia with marked metaphyseal changes

Spondyloepiphyseal dysplasia (SED) with marked metaphyseal changes is a group of rare skeletal disorders. People with SED with marked metaphyseal changes have abnormalities of the spine (spondylo-) and the regions near the ends (metaphyses) and at the ends (epiphyses) of the long bones in the arms and legs. The severity of the signs and symptoms can vary from person to person.

People with SED with marked metaphyseal changes may have a short torso, shortened arms and legs, and flattened bones of the spine (platyspondyly), which all lead to short stature. People with SED with marked metaphyseal changes may develop abnormal side-to-side and front-to-back curvature of the spine (scoliosis and kyphosis, often called kyphoscoliosis when they occur together). This abnormal spinal curvature may be severe and can cause problems with breathing. Instability of the spinal bones (vertebrae) in the neck can cause these bones to shift, which increases the risk of damage to the spinal cord. 

Other features of SED with marked metaphyseal changes may include legs that curve outward or inward (valgus or varus deformity) and irregular bone formation (ossification) in the long bones. Changes in the position of the thigh bone where it meets the hip joint can cause difficulty walking.  Affected individuals may also have joint pain, swollen joints, and joint deformities (contractures). Arthritis may develop early in life.

The conditions that make up SED with marked metaphyseal changes were once thought to be distinct disorders, but they are now considered to be part of the same disease spectrum. These conditions include spondyloepimetaphyseal dysplasia, Strudwick type (SEMD-S); spondylometaphyseal dysplasia, Algerian type (SMD-A); spondyloepiphyseal dysplasia, Stanescu type (SED-S); some cases of spondylometaphyseal dysplasia, corner fracture type (SMDCF); and dysspondyloenchondromatosis (DSC).