Clinical disorders of the erythrocyte membrane skeleton.

With advances in understanding of the biochemistry of the erythrocyte membrane skeleton, the molecular basis of some of the hereditary anemias has been determined. Distinct spectrin abnormalities have been identified in spherocytosis and elliptocytosis. Protein 4.1 variants may result in elliptocytosis or may be clinically silent. While abnormalities of other proteins have not yet been identified, it is likely that variants of ankyrin and perhaps other proteins will eventually be identified as defects in these biochemically heterogeneous disorders of blood. Proteins related to spectrin, ankyrin, and protein 4.1 have been found in multiple other tissues, including brain, lymphocytes, and connective tissue, and the role of these proteins is being studied. Identification of the functional abnormalities and molecular biology of abnormal erythrocyte membrane proteins is therefore likely to have direct relevance to understanding of other cell types and diseases.