Merck Manual

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Hemoglobin C Disease


Evan M. Braunstein

, MD, PhD, Johns Hopkins School of Medicine

Last full review/revision Sep 2020| Content last modified Sep 2020
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Hemoglobin C disease is a hemoglobinopathy that causes symptoms of a hemolytic anemia.

The prevalence of hemoglobin (Hb) C in blacks in the US is about 2 to 3%. Heterozygotes are asymptomatic. Homozyotes usually have a mild chronic hemolytic anemia, splenomegaly, and symptoms consistent with anemia. Cholelithiasis is the most common complication, and splenic sequestration is possible.

Hemoglobin C disease is suspected in all patients with a family history and evidence of a hemolytic anemia, particularly in adults with splenomegaly. The anemia is usually mild but can be severe.

The peripheral smear is microcytic, with frequent target cells, spherocytes, and, rarely, crystal-containing red blood cells (RBCs). Nucleated RBCs may be present. The RBCs do not sickle. On electrophoresis, the hemoglobin is type C. In heterozygotes, the only laboratory abnormality is centrally targeted RBCs.

No specific treatment is recommended. Anemia usually is not severe enough to require blood transfusion.

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