Sickle Cell Anemia
A microscopic view of a peripheral blood smear depicting sickle-cells. Sickle-cells can occur when a person inherits a single point mutation in the gene for hemoglobin, the oxygen carrying protein of red blood cells, resulting in an abnormal form of hemoglobin called hemoglobin S. With the inheritance of one gene (heterozygous), one is said to have sickle cell trait and rarely does illness occur. Sickle-cell disease or sickle-cell anemia occurs when one inherits two copies in the gene (homozygous).
Hemoglobin S molecules adhere to each other in the absence of oxygen leading to a distorted sickle shaped red blood cell. As the cycle of becoming oxygenated within the lungs then deoxygenated upon release of oxygen within the tissues, happens over and over again, the cell wall becomes rigid. With rigid cell walls and a sickle shape sickle cells cause blockages within blood vessels resulting in pain, tissue, and organ damage.