Sickle cell disease is a genetic blood disorder that affects the hemoglobin, the molecule found in red blood cells that carry oxygen throughout the body. The sickle gene changes the makeup of the red blood cells by changing the normal hemoglobin into hemoglobin S, which causes the red blood cell to be distorted. (Sejeant, 1992). A normal red blood cell is smooth surfaced, flexible, and round while the affected one is rigid, elongated, and takes the form of a sickle, crescent shape. (Sejeant, 1992). The concave shape gets stuck easily in the blood vessels of humans, and creates clots, preventing the flow of oxygen by the already ineffective transport of it by the abnormal hemoglobin .(Hampton, 2000). Hemoglobin has four protein subunits, two alpha-globin, and two beta-globin. The disease is caused by a mutation in the beta-globin gene. (Genetics Home Reference, 2012). The sickle cells die prematurely. Normal red blood cells live for up to 120 days while sickle red blood cells only live 10-20 days. (Learn Genetics, 2013).
Sickle cell anemia is the most common form of Sickle cell disease (both beta-globin are replaced by hemoglobin S), but other form also exist, such as Sickle C Hemoglobin (a milder form, one beta-globin is replaced by hemoglobin C), Sickle Beta Zero Thalassemia (which is treated the same as Sickle Cell Anemia, hemoglobin S and hemoglobin s-beta thalassemia) and Sickle Beta Plus Thalassemia (mildest form, one replaces one beta-globin with hemoglobin s-beta thalassemia),and Hemoglobin C disease (minor abnormality of the hemoglobin, one beta-globin is replaced by Hemoglobin C). (Vedro, 2002).
Sickle cell anemia is the most common form of Sickle cell disease (both beta-globin are replaced by hemoglobin S), but other form also exist, such as Sickle C Hemoglobin (a milder form, one beta-globin is replaced by hemoglobin C), Sickle Beta Zero Thalassemia (which is treated the same as Sickle Cell Anemia, hemoglobin S and hemoglobin s-beta thalassemia) and Sickle Beta Plus Thalassemia (mildest form, one replaces one beta-globin with hemoglobin s-beta thalassemia),and Hemoglobin C disease (minor abnormality of the hemoglobin, one beta-globin is replaced by Hemoglobin C). (Vedro, 2002).