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Hemoglobin S-C Disease

By

Evan M. Braunstein

, MD, PhD, Johns Hopkins University School of Medicine

Last full review/revision Jun 2022| Content last modified Sep 2022
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The heterozygous S-C combination is more common than homozygous Hb C disease Hemoglobin C Disease Hemoglobin C disease is a hemoglobinopathy that causes symptoms of a hemolytic anemia. (See also Overview of Hemolytic Anemia.) The prevalence of detectable hemoglobin (Hb) C in people in the... read more . This is because of the high prevalence of hemoglobin (Hb) S trait (which is responsible for sickle cell disease Sickle Cell Disease Sickle cell disease (a hemoglobinopathy) causes a chronic hemolytic anemia occurring almost exclusively in people with African ancestry. It is caused by homozygous inheritance of genes for hemoglobin... read more 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 normal hemoglobin levels.

Symptoms are similar to the symptoms of sickle cell disease Symptoms and Signs Sickle cell disease (a hemoglobinopathy) causes a chronic hemolytic anemia occurring almost exclusively in people with African ancestry. It is caused by homozygous inheritance of genes for hemoglobin... read more Symptoms and Signs , 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.

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.

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