Review of Skeletal Dysplasias

• Symmetric short stature
  • Short limb
    • Rhizomelic: Proximal humeri and femurs most severely shortened.
      • Achondroplasia: Shortening and bowing of the extremities with exaggerated lumbar lordosis. Enlarged cranium with frontal bossing, sunken nasal root, and prognathism. Narrow spinal canal due to narrow interpedicular distance and short pedicles. The interpedicular distances also narrow as we move down the spine. Decreased vertebral body heights and posterior vertebral body scalloping. Short and broad ribs. Champagne glass pelvis: flattened iliac bones give rise to a pelvic inlet that supposedly resembles a champagne glass.
      • Hypochondroplasia: Milder form achondroplasia. The characteristic facial findings of achondroplasia are not seen clinically
      • Thanatophoric dwarfism: Findings are more severe versions of those seen with achondroplasia, especially in the ribs.
    • Mesomelic: Radius/ulna and tibia/fibula most severely shortened.
      • Campomelic dysplasia: From the Greek Campe, meaning bent or crooked, which describes the anterolateral tibial bowing. Also seen are an enlarged cranium, micrognathia, hypoplastic scapular wings, absence of thoracic pedicles on radiographs, kyphoscoliosis, 11 pairs of ribs, dislocated hips, and vertically oriented narrow iliac wings. A good summary with radiographic images can be found at NIH's Gene Reviews
      • Dyschondrosteoses: Rare form of mesomelic dysplasia. Characterized by short stature and a Madelung deformity.
    • Acromelic: Distal appendicular skeleton (metacarpals/metatarsals and phalanges) most severely shortened.
      • Jeune syndrome (asphyxiating thoracic dystrophy): Usually fatal. Infants present with shortness of breath due to short ribs and a tubular chest. Polydactyly in about 30%. Flat acetabular angles. Trident acetabulum: Flat acetabular roofs with downward spikelike projections at the medial and lateral aspects of the roofs.
      • Ellis-van Creveld syndrome (chondroectodermal dysplasia): Triad of short stature, ectodermal dysplasia (hypoplastic, brittle nails and thin, sparse hair), and polydactyly. More common in the Amish. Similar findings to Jeune syndrome, but the infants generally survive. Also seen are wormian bones.
      • Pyknodysostosis: Generalized osteosclerosis, short stubby hands (distal phalanges may mimic acroosteolysis), brittle bones, wormian bones and hypoplastic facial bones. Supposedly Henri de Toulouse-Lautrec had this condition.
  • Short trunk
    • Metaphyseal chondrodysplasias: Epiphyses and the vertebrae minimally affected.
      • Jansen: Irregular metaphyses and widened growth plates. Autosomal dominant.
      • Schmid: Irregular metaphyses and widened growth plates. Autosomal dominant.
      • McCusik: Irregular metaphyses, flat epiphyses and irregular zones of provisional calcification.
      • Shwachman-Diamond: Irregular metaphyses, flat epiphyses and irregular zones of provisional calcification. Pancreatic exocrine insufficiency.
    • Mucopolysaccharidoses: Osteopenia, enlarged skull with a thick calvarium, hypoplastic sinuses, J-shaped sella, anteroinferior beaking of ovoid vertebral bodies at the thoracolumbar junction, dysplastic capital femoral epiphyses, and short and wide metacarpals and phalanges of the hands.
      • Hurler syndrome: Mucopolysaccharidosis type I. Most common.
      • Hunter syndrome: Mucopolysaccharidosis type II.
      • Sanfilippo syndrome: Mucopolysaccharidosis type III.
      • Morquio disease: Mucopolysaccharidosis type IV.
    • Mucolipidoses: Clinically and radiographically identical to mucopolysaccharidoses.
    • Sphingolipidoses: Clinically and radiographically identical to mucopolysaccharidoses.
    • Spondylometaphyseal dysplasia (Kozlowski type): Flat vertebral bodies often associated with coronal clefts and anterior wedging. Broad and irregular metaphyses, particularly of the lower limbs.
    • Spondyloepiphyseal dysplasia: Congenita and tarda. Tarda form is an X-linked recessive trait. Usually becomes symptomatic by 5 - 10 years of age. Characterized by irregular, flattened epiphyses that can lead to early osteoarthritis. Flat vertebral bodies. Can have odontoid hypoplasia.
    • Kniest dysplasia:
  • Proportionate short stature
    • Normal: 2% of all children measure below the 3rd percentile.
    • Systemic disease: Pituitary, renal, nutritional, or chromosomal issues
    • Cleidocranial dysplasia: Incomplete ossification of the clavicle, bell-shaped thorax, enlarged calvaria with frontal bossing and open fontanelles, wormian bones, brachydactyly with hypoplastic distal phalanges, hypoplasia of the pelvis with widened symphysis pubis, supernumerary teeth and severe dental anomalies.
    • Osteopetrosis:
• Asymmetric short stature
  • Osteogenesis imperfecta:
  • Multiple enchondromatosis:
  • Multiple hereditary cartilaginous exostoses:
  • Diaphyseal aclasis:
  • Conradi-Hünermann syndrome: Autosomal dominant chondrodysplasia punctata.

References

• Blickman JG and Vanderschueren G. Chapter 7: Skeletal System. in Pediatric Radiology: The Requisites (third ed). Blickman JG, Parker BR, and Barnes PD, eds. Mosby, 2009.
• Maizlin ZV, Kuruvilla M, Clement JJ, Vos PM, Brown JA. Radiologic signs of weapons and munitions: How will noncombatants recognize them? AJR Am J Roentgenol. 2010 Aug;195(2):W96-104.
• Mundlos S. Cleidocranial dysplasia: clinical and molecular genetics. J Med Genet. 1999 Mar;36(3):177-82.
• Roche CJ, O'Keeffe DP, Lee WK, Duddalwar VA, Torreggiani WC, Curtis JM. Selections from the buffet of food signs in radiology. Radiographics. 2002 Nov-Dec;22(6):1369-84.
• Spranger JW. Metaphyseal chondrodysplasia. Postgrad Med J. 1977 Aug;53(622):480-7.
• Thomas PS, Nevin NC. Spondylometaphyseal dysplasia. AJR Am J Roentgenol. 1977 Jan;128(1):89-93.