Hemoglobin S-C disease is a form of sickle cell disease.
(See also Overview of Hemolytic Anemia and Sickle Cell Disease.)
The heterozygous S-C combination is more common than homozygous Hb C disease. This is because of the high prevalence of hemoglobin (Hb) S trait (which is responsible for sickle cell disease), particularly in people with African ancestry. The anemia in Hb S-C disease is milder than the anemia in sickle cell disease; some patients even have hemoglobin levels that are close to normal.
Symptoms are similar to the symptoms of sickle cell disease but are usually less frequent. However, patients with Hb S-C disease can also experience life-threatening manifestations, such as acute chest syndrome and multiorgan system failure. Gross hematuria, retinal hemorrhages, and aseptic necrosis of the femoral head are common. Splenomegaly may be present and some patients may develop functional asplenia though at a later age than in sickle cell anemia.
Hemoglobin S-C disease is suspected in patients whose clinical features suggest sickle cell disease or whose red blood cells 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 hemoglobin electrophoresis establishes the diagnosis.
Treatment can be similar to the treatment of sickle cell disease but is determined by the severity of the symptoms. Data on the use of hydroxyurea in HbS-C disease is limited.
