Hemoglobin C disease

Like HbS, HbC is a hemoglobin variant that has a single amino acid substitution in the sixth position of the β-globin chain (Fig. 1). In HbC, however, a lysine is substituted for the glutamate (as compared with a valine substitution in HbS). [Note: This substitution causes HbC to move more slowly toward the anode than HbA or HbS does (Fig. 2).] Rare patients homozygous for HbC generally have a relatively mild, chronic hemolytic anemia. They do not suffer from infarctive crises, and no specific therapy is required.

Figure 1: Amino acid substitutions in hemoglobin S (HbS) and hemoglobin C (HbC).

Figure 2: Diagram of hemoglobins (HbA), (HbS), and (HbC) after electrophoresis.