Hereditary spherocytosis is the most common inherited anemia in persons of northern European descent. In 75 percent of cases, the condition is inherited in an autosomal dominant fashion. Patients usually present with splenomegaly, jaundice and anemia. A deficiency of the cytoskeletal protein spectrin is believed to underlie this hemolytic state. Affected individuals display a tendency to form pigmented (bilirubin) gallstones. Splenectomy may be essentially curative in the majority of patients.