Hereditary spherocytosis

Hereditary spherocytosis

Updated: 07/14/2024

© Jun Wang, MD, PhD

 

General features

  • Most common cause of hemolytic anemia due to a red cell membrane defect
  • Caused by mutations in genes for membrane/cytoskeletal proteins
  • Autosomal dominant for mutations in ANK1, SPTB or SLC4A1
  • Autosomal recessive for SPTA1 and EPB42
  • Hemolysis due to impaired RBC elasticity

Pathogenesis

  • Variants in one of the five genes (ANK1, SPTA1, SPTB, SLC4A1, and EBP42) that encode the erythrocyte membrane proteins ankyrin, alpha-spectrin, beta-spectrin, band 3, and band 4.2, respectively
  • Mutations of these proteins cause reduced membrane stability

 


Clinical features

  • Clinical features: splenomegaly, anemia, jaundice
  • Splenectomy in severe cases usually curative

Laboratory findings

  • Peripheral blood

o   Spherocytes: small, hyperchromic RBC lacking the central zone of pallor area

o   Normal MCH, high MCHC

o   Normal to decreased MCV

o   Normal to increased RDW

o   Increased reticulocytes

  • Chemistries:

o   Increased LDH and indirect bilirubin

o   Decreased haptoglobin

  • Bone marrow: Erythroid hyperplasia
  • Elevated reticulocyte count

Diagnosis

  • Family history
  • Increased osmotic fragility
  • Confirmation tests: EMA binding, osmotic fragility, or osmotic gradient ektacytometry (OGE)
  • Genetic testing
  • DAT (direct antiglobulin test) to exclude autoimmune causes of spherocytosis and hemolysis

Management

  • Preventing or minimizing complications of chronic hemolysis and anemia
  • Treatment of hyperbilirubinemia
  • Folate supplementation
  • Erythropoietin
  • Transfusion
  • Splenectomy

 

 

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Anemia

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Practice questions Anemia I

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