Which of the following proteins is not altered in hereditary spherocytosis (HS)?A. Pyruvate kinase
The underlying abnormality in hereditary spherocytosis (HS) is an inherited dysfunction or deficiency in one of the erythrocyte membrane proteins (spectrin, ankyrin, band 3 protein, or protein 4.2), which results in destabilization of the membrane lipid bilayer. This destabilization allows a release oflipids from the membrane, causing a reduction in membrane surface area and a lack of deformability, leading to sequestration and destruction of the spherocytic erythrocytes in the spleen. Although less common than glucose-6-phosphate dehydrogenase (G6PD) deficiency overall, pyruvate kinase deficiency is the most common RBC enzyme deficiency to cause congenital chronic hemolytic anemia.