Spondyloepiphyseal Dysplasia



  • Spondyloepiphyseal dysplasia (SED)

  • Group of generalized skeletal dysplasias primarily involving vertebrae, proximal epiphyseal centers

  • Affected patients demonstrate short trunk, neck, and limbs with normal hand and foot size


  • Platyspondyly, vertebral hypoplasia & underossification, abnormal epiphyses

  • ± pannus at C1/C2, os odontoideum

  • Delayed ossification of capital femoral epiphysis → femoral head flattening, premature osteoarthritis

Top Differential Diagnoses

  • Spondylometaphyseal dysplasia

  • Spondyloepimetaphyseal dysplasia

  • Multiple epiphyseal dysplasia


  • SED congenita

    • Abnormal type II collagen synthesis

  • SED tarda

    • SEDL gene mutation (vesicular transport protein)

Clinical Issues

  • SED congenita: Diagnosed at birth, short proximal limbs with normal hand, foot size

  • SED tarda: Normal appearance at birth, subsequent identification of disproportionately short stature in adolescence or adulthood

Diagnostic Checklist

  • Consider SED congenita for platyspondyly, dysplastic epiphyses

  • Consider SED tarda in adults with short trunk, early symmetric large joint osteoarthritis

Lateral cervical radiograph (kyphosis, myelopathy) obtained in extension shows platyspondyly and delayed ossification status. The odontoid process is hypoplastic or underossified, rendering evaluation for atlantoaxial subluxation difficult.

Sagittal T1WI MR (kyphosis, myelopathy) of the cervical spine reveals characteristic abnormal vertebral shape as well as a large odontoid process with delayed tip ossification. No spinal cord compression is demonstrated.

Lateral radiograph of the thoracolumbar spine (kyphosis, myelopathy) demonstrates characteristic platyspondyly in addition to focal kyphosis at the thoracolumbar junction secondary to a hypoplastic L2 vertebra .

Sagittal T2WI MR (kyphosis, myelopathy) of the thoracolumbar spine confirms significant stenosis of the lower thoracic spinal canal producing focal spinal cord compression and abnormal spinal cord T2 hyperintensity .


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