Hereditary spherocytosis is due to -

Ans. is 'a' i.e., Spectrin deficiency Pathogensis of hereditary spherocytosis o Loss of membrane cytoskeleton proteins (ankyrin, spectrin, Band 3, 4.2) results in reduced membrane stability. Reduced membrane stability leads to spontaneous loss of membrane fragments during exposure to shear stresses in the circulation. The loss of membrane relative to cytoplasm forces the cells to assume the smallest possible diameter for a given volume --> Cells become microspherocytes. Because of their spheroidal shape and reduced membrane plasticity, red cells become less deformable and are trapped in to spleen as they are unable to pass through the interendothelial fenestrations of the venous sinusoids. In the splenic sinusoides, red cells are phagocytosed by RE cells --> Extravascular hemolvsis.