Diastrophic Dysplasia

  • Etiology: Autosomal recessive
  • Imaging Long Bones:
    — Shortened tubular bones with metaphyseal widening and rounding
    — Epiphyses show delayed development (especially proximal femoral epiphyses) and are flattened and deformed (crescent shaped)
    — Tibial ossification center medially placed
    — Disproportionate shortening of ulna and fibula
    — Radial heads dislocated
  • Imaging Hands and Feet:
    — Bones are small especially first metacarpal which can be round
    — Epiphyses may be irregular
    — Carpal bones may ossify prematurely, be deformed, have accessory ossification centers
    — Feet have equinovarus deformity, tarsal valgus deformity and metatarsus adductus
  • Imaging Joints:
    — Narrowed joints in hips and ankles
  • Imaging Femurs:
    — Broad intertrochanteric regions with short femoral necks
  • Imaging Spine:
    — Odontoid dysplasia
    — Irregular vertebral bodies causing cervical and thoracic kyphosis and scoliosis
    — Lumbar lordosis
    — Progressive narrowing of interpediculate distances in lower lumbar vertebrae
  • DDX:
  • Complications:
  • Treatment:
  • Clinical:
    — Short limbed (rhizomelic) with normal trunk
    — Disastrophic = twisted and describes twisted body habitus due to joint flexion contractures and kyphoscoliosis
    — Short and broad hands and clubfeet
    — Thumbs and toes held in abducted hitchhiker’s position
    — Cystic masses in earlobes
    — Dislocated joints
    — Cleft palate

Radiology Cases of Diastrophic Dysplasia

Radiograph of the hands in diastrophic dysplasia
AP radiograph of the hand shows abducted (hitchhiker) thumb, irregular deformity and shortening of the phalanges and metacarpal bones, and bifid second through fourth middle phalanges.
Spine radiograph of diastrophic dysplasia
AP radiograph of the thoracic and lumbar spine shows a mild thoracic scoliosis convex right and progressive narrowing of the distance between the pedicles descending through the lumbar spine (interpediculate narrowing).
Radiograph of spine in diastrophic dysplasia
AP radiograph of the thoracic and lumbar spine (left) shows thoracic scoliosis convex right as well as progressive narrowing of the distance between the pedicles descending through the lumbar spine (interpediculate narrowing). The lateral radiograph of the thoracic and lumbar spine (right) shows an irregular shape of the anterior aspect of the vertebral bodies at the thoracolumbar junction, resulting in a kyphotic deformity to the spine.
Radiograph of diastrophic dysplasia
AP radiograph of the pelvis shows absence of the femoral epiphyses. The femoral necks are short and broad with a widened intertrochanteric distance.
Radiograph of extremities in disastrophic dysplasia
AP radiograph of the lower extremities shows shortened femurs bilaterally with flattened distal epiphyses.
Radiograph of feet in diastrophic dysplasia
AP radiograph of the feet (above) shows irregular deformity and shortening of the metatarsal bones. Crescent-shaped flattened epiphyses are present. Forefoot varus, hindfoot varus and hindfoot equinus (below) are also present.