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Case 63 - Discussion

Hematopathology Case

 

Hereditary Elliptocytosis

  • Autosomal dominant, defective spectrin α chain (SPTA1) in 60% of cases

  • Elliptocytes >25% of RBCs, length 2 > width

  • Subtypes

    • Common type: African, heterozygous-mild; homozygous-moderate to severe

      Hereditary pyropoikilocytosis (HPP)

      • Severe form of the common type, defective spectrin

      • Very sensitive to heat: HPP cells fragment in ~10 mins at 45-46C or 6 hours at 37C, whereas normal RBCs do not fragment until heated to 49C

      • Extreme variability of RBC morphology, with RBC fragments, microspherocytes, membrane budding, elliptocytes, oval macrocytes, trangulocytes and polychromasia

    • Spherocytic type: HS + HE, clinically mild

    • Stomatocytic type: Band 3 defect, Malaysia, P. vivax protection, clinically mild

  • DDX: iron deficiency anemia, vitamin B12 or folate deficiency, myelodysplasia, and myelophthisis. Elliptocytes < 25%