What is hereditary spherocytosis? pathogenesis, morphology, and clinical features.
Hereditary Spherocytosis This disorder stems from inherited (intrinsic) defects in the red cell membrane. Leads to formation of spherocytes — non-deformable cells that are highly vulnerable to sequestration and destruction in the spleen. Usually transmitted as an autosomal dominant trait . A more severe autosomal recessive form affects a small minority of patients. Pathogenesis Caused by inherited defects in the membrane skeleton , a network of proteins stabilizing the lipid bilayer of red cells. Major membrane skeleton protein: spectrin — a long, flexible heterodimer that: Self-associates at one end. Binds short actin filaments at the other. These interactions form a two-dimensional meshwork , connected to transmembrane proteins ( band 3 and glycophorin ) via linker proteins : ankyrin band 4.2 band 4.1 Most common mutations involve: ankyrin band 3 spectrin Pathogenic mutations: Weaken vertical interactions between the m...