What is Hereditary spherocytosis?

A congenital defect of spectrin [MIM*182860], the main component of the erythrocyte cell membrane, which becomes abnormally permeable to sodium, resulting in thickened and almost spheric erythrocytes that are fragile and susceptible to spontaneous hemolysis, with decreased survival in the circulation; results in chronic anemia with reticulocytosis, episodes of mild jaundice due to hemolysis, and acute crises with gallstones, fever, and abdominal pain; symptomatology is highly variable; autosomal dominant inheritance, caused by mutation in the ankyrin gene (ANK1) on 8p. However, as with elliptocytosis, there is an autosomal recessive form [MIM*270970], caused by mutation in the alpha-spectrin 1 gene (SPTA1) on chromosome 1q.