Merck Manual

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Hemoglobin C Disease


Evan M. Braunstein

, MD, PhD, Johns Hopkins University School of Medicine

Reviewed/Revised Jun 2022 | Modified Sep 2022
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The prevalence of detectable hemoglobin (Hb) C in people in the US with African ancestry is about 2 to 3%. Patients who are heterozygotes are asymptomatic. Those who are homozygotes usually have a mild chronic hemolytic anemia, splenomegaly, and symptoms consistent with anemia. Cholelithiasis Cholelithiasis Cholelithiasis is the presence of one or more calculi (gallstones) in the gallbladder. In developed countries, about 10% of adults and 20% of people > 65 years have gallstones. Gallstones... read more 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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