Spondyloepiphyseal Dysplasia

KEY FACTS

Terminology

• 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

Imaging

• 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

Pathology

• 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

IMAGING