Hereditary spherocytosis (HS) is a common inherited anaemia in northern Europe characterized by the presence of spherocytic red cells and by heterogeneous clinical presentation, and heterogeneous molecular basis and inheritance. The primary molecular defects reside in the red blood cell membrane, particularly in proteins involved in the vertical interactions between the membrane skeleton and the lipid bilayer. Defects in these interactions lead to the loss of red cell surface area and to the spheroidal shape of the erythrocyte in particular loss of the membrane elasticity and mechanical stability. Severe HS is often associated with a substantial reduction of, and (or) dysfunction of, the affected membrane protein(s). Hereditary spherocytosis stems from mutations in one of the genes encoding ankyrin-1 (ANKI), alpha spectrin (SPTA1) and beta spectrin (SPTB), the anion exchanger 1 (SLC4A 1), and protein 4.2 (EPB42). Inheritance of HS is usually (75%) autosomal, dominant. Recessive and nondominant cases are mostly found in HS associated with ANK1, SPTA1 and SPTB genes.