Hereditary spherocytosis (HS)

(Lancet 2008;372:1411)

• Defect in cytoskeleton of RBC membrane (ankyrin, α- and β-spectrin, band 3, & pallidin)

• Most common in N. European populations (1/5000 births); ⊕ FHx (75% of Pts)

• Anemia, jaundice (mostly neonates), splenomegaly, pigmented gallstones

• Diagnosis: spherocytes on smear, ⊕ osmotic fragility test (~80% Se), ↓ eosin-5-maleimide (EMA) binding (93% Se; 99% Sp; Haemat 2012;97:516), acidified glycerol lysis test (Se 95%)

• Treatment: folate, transfusions, splenectomy for moderate and severe HS (balance w/ ↑ risk of future thrombosis and infection; J Thromb Haemost 2008;6:1289)