Sideroblastic anemia

• Description: anemia caused by defective heme metabolism, which leads to iron trapping inside the mitochondria
• Etiology
  • Inherited: X-linked sideroblastic anemia due to a δ-ALA-synthase gene defect
  • Acquired
    • Vitamin B6 deficiency
    • Lead poisoning
    • Alcohol use disorder
    • Drugs (e.g., chloramphenicol, isoniazid, linezolid)
• Diagnostics
  • CBC: microcytic anemia
    • Serum iron studies
    • High ferritin
    • High iron
    • High transferrin saturation
    • Normal/low TIBC
  • Peripheral blood smear
    • Basophilic stippling of RBCs t
      • Basophilic stippling represents the aggregation and precipitation of residual rRNA within the red blood cell cytoplasm. Lead inhibits the enzyme pyrimidine 5’-nucleotidase. This enzyme normally degrades RNA during RBC maturation. Inhibition prevents breakdown, causing rRNA to clump.
  • Prussian blue staining of bone marrow: ringed sideroblasts