Differential diagnosis of skeletal dysplasias

Approach to the DDX of skeletal dysplasias:

  • Types of limb shortening
    — Rhizomelic – proximal appendicular skeleton – humerus, femur
    — Mesomelic – middle appendicular skeleton – radius-ulna, tibia-fibula
    — Acromelic – distal appendicular skeleton – metacarpals, metatarsals, phalanges
    — Micromelic – entire appendicular skeleton
  • Lethal skeletal dysplasias due to short ribs leading to thoracic dysplasia
    — Rhizomelic – thanatophoric dysplasia, achondrogenesis
    — Mesomelic – campomelic dysplasia
    — Acromelic – asphyxiating thoracic dystrophy, chondroectodermal dysplasia, short rib polydactyly
  • Non-lethal skeletal dysplasias
    — Rhizomelic – achondroplasia, chondrodysplasia punctata, diastrophic dysplasia, spondyloepiphyseal dysplasia
    — Mesomelic –
    — Acromelic – pyknodysostosis
  • Shortened body portion
    — Short limbed, normal trunk
    — Rhizomelic – achondroplasia
    — Mesomelic –
    — Acromelic –
    — Short trunk, normal limbed – chondrodysplasia punctata, spondyloepiphyseal dysplasia
    — Short trunk and limbed (Proportionate) – diastrophic dysplasia, mucopolysaccharidoses