Hemoglobin S-C Disease
(See also Overview of Hemolytic Anemia.)
Hemoglobin S-C disease is a hemoglobinopathy that causes symptoms similar to those of sickle cell disease, but usually less severe.
Because 10% of blacks carry the Hb S trait (that is responsible for sickle cell disease), the heterozygous S-C combination is more common than homozygous Hb C disease. The anemia in Hb S-C disease is milder than the anemia in sickle cell disease; some patients even have normal Hb levels.
Symptoms are similar to the symptoms of sickle cell disease, but are usually less frequent and less severe. However, gross hematuria, retinal hemorrhages, and aseptic necrosis of the femoral head are common. Splenomegaly may be present.
Hb S-C disease is suspected in patients whose clinical features suggest sickle cell disease or whose RBCs demonstrate sickling. Stained blood smears show target cells, spherocytes, and rarely sickle cells or oat-shaped cells. Sickling is identified in a sickling preparation, and Hb electrophoresis establishes the diagnosis.
Treatment can be similar to the treatment of sickle cell disease but is determined by severity of symptoms.