• Description
  • Intrinsic defect of erythroid progenitor cells → ↑ apoptosis
  • Usually autosomal dominant inheritance or associated with impaired ribosome synthesis mutations
  • Rapid onset of macrocytic (nonmegaloblastic) anemia in infancy (usually diagnosed within the first year of life)
• Additional clinical features: physical abnormalities manifest in ∼50% of affected individuals
  • Fatigue, poor feeding
  • Short stature, webbed neck
  • Upper extremity malformations (e.g., triphalangeal thumbs)
  • Microcephaly, micrognathia
  • Hypertelorism, flat nasal bridge, cleft palate
  • Congenital cataracts or glaucoma
  • Atrial and ventricular septal defects
• Diagnostics
  • Electrophoresis
    • Elevated HbF levels
    • Low total Hb levels
  • Specific laboratory findings
    • Elevated erythrocyte adenosine deaminase levels (eADA)
    • Increased expression of i antigen in RBCs