The red cell membrane is comprised of a lipid bilayer studded with transmembrane proteins, and laminated by a protein network, the membrane skeleton, at the surface of the inner monolayer. The erythrocyte owes its mechanical properties to the membrane skeleton. Hereditary spherocytosis, hereditary elliptocytosis or poikilocytosis, Southeast Asian ovalocytosis are hereditary hemolytic anemias, due to mutations in the genes encoding ankyrin, the anion exchanger, spectrin, protein 4.1 or protein 4.2, which are main proteins of the membrane. Recent advances in the field have led to fundamental questions.