Hemoglobin C, S-C, and E diseases are inherited conditions characterized by abnormally shaped red blood cells and chronic anemia that is caused by excessive destruction of red blood cells.

Hemoglobin C, S, and E are abnormal forms of hemoglobin (the protein in red blood cells that carries oxygen). These abnormal forms of hemoglobin result from inheriting an abnormal gene.

Hemoglobin C disease occurs mostly in blacks. One copy of the gene that causes hemoglobin C disease is present in 2 to 3% of blacks in the United States. However, people must inherit two copies of the abnormal gene to develop the disease. In general, symptoms are few. Anemia varies in severity. People who have this disease, particularly children, may have episodes of abdominal and joint pain, an enlarged spleen, and mild jaundice, but they do not have severe crises, as occur in sickle cell disease.

Hemoglobin S-C disease occurs in people who have one copy of the gene for sickle cell disease and one copy of the gene for hemoglobin C disease. Hemoglobin S-C disease is more common than hemoglobin C disease, and its symptoms are similar to those of sickle cell disease but milder.

Hemoglobin E disease affects primarily people from Southeast Asia. This disease produces anemia but none of the other symptoms that occur in sickle cell disease and hemoglobin C disease. Diagnosis is by a blood test called hemoglobin electrophoresis. Treatment varies depending on the severity of symptoms but can include some of the same treatments that are used in people with sickle cell disease.

Last full review/revision June 2008 by Alan E. Lichtin, MD