Spectrin is the major constituent of the cytoskeletal network underlying the erythrocyte plasma membrane. Spectrin associates with band 4.1 and actin to form the cytoskeletal superstructure of the erythrocyte plasma membrane. Defects in spectrin are the cause of elliptocytosis type 2 (EL2). EL2 is a Rhesus-unlinked form of hereditary elliptocytosis, a genetically heterogeneous, autosomal dominant hematologic disorder. EL2 is characterized by variable hemolytic anemia and elliptical or oval red cell shape.