Hemoglobin C

Hemoglobin C ( HbC or C Hb ) is an abnormal hemoglobin, in which a glutamic acid has been substituted with a lysine residue at the sixth position of the β -globin chain ( E6K substitution).

Clinical Significance

This mutated form of the normal reduced moldability of the host red blood cells, which in turn causes a hemoglobinopathy. Among those in which the mutation is heterozygous, is about 28-44 % of the hemoglobin of the HBC and there is no anemia. In persons in whom the mutation is homozygous, there almost the entire Hömoglobin from the HBC - form, which in turn results in a low hemolytic anemia.

Child location

Target cells microspherocytes and HbC crystals were found in the blood smear of homozygous patients.

Combinations with other conditions

People with the sickle cell -hemoglobin C ( HBSC ), the gene for HbS have inherited from one parent and the gene for HbC from the other parents Splits: They are thus " heterozygous ". Since HbC does not polymerize as readily as HbS, there is less sickling and thus less sickle cells. The blood smear usually shows target cells and only a few sickle cells. There is less acute vasoconstrictive events. However, persons with hemoglobin SC disease ( HBSC ) more significant retinopathy, ischemic necrosis of the bone, and priapism, such as with a pure SS disease.

Epidemiology

Hemoglobin C genes were found in the United States, at 2-3 % of blacks, while 8 % of whites hemoglobin S genes showed. Thus, the hemoglobin SC disease is significantly more common than the hemoglobin CC disease. Hemoglobin C is mainly found among the Yoruba. Similarly, it is found in areas of West Africa, such as Ghana, where the Yorubas had once lived (MAN Volume 56, March 1956, pages 34-36).