Hemoglobin S

(HbS); an abnormal hemoglobin that renders erythrocytes subject to an abnormal change in shape (sickling) and hemolysis at reduced oxygen tension or upon cellular dehydration

Description
HbS makes up 70–100% of hemoglobin in persons with homozygous sickle cell anemia. The HbS mutation in the heterozygous state causes a mild anemia but also confers resistance to malaria, thus bringing about the wide distribution of HbS in countries affected by malaria. The resistance presumably results from the high turnover rate of sickle-heterozygous [erythrocyte]]s, which prevents completion of the erythrocyte-resident developmental stage of the malaria-causing Plasmodium parasites. The HbS mutation in its heterozygous state also leads to clinically important compound phenotypes with other (e.g. thalassemic) &#946;-globin mutations. Syn sickle cell hemoglobin; See hemoglobin, HbSC disease, HbSD disease