Sickle cell anemia is an inherited disorder of the red blood cells found most commonly in people of African descent. A person who inherits two sickle cell genes will develop sickle cell anemia. When only one sickle cell gene is passed on, the person will only occasionally experience symptoms of the disease under low-oxygen, high altitude conditions. One in 10 African Americans carries the sickle cell trait. One in 625 has sickle cell anemia.
Hemoglobin helps red blood cells carry oxygen from the lungs to the rest of the body. Sickle cell anemia is present in the blood when the patient’s body produces sickle-shaped hemoglobin S rather than the normal, round hemoglobin A. When red blood cells become sickle-shaped (like a crescent), they have difficulty passing through small blood vessels.
Red blood cells containing mostly Hemoglobin S do not live as long as normal red blood cells (120 days compared to 16 days). They also may become stiff and distorted in shape. When sickle-shaped cells block small blood vessels, less blood can circulate. Tissue that does not receive normal blood flow will become damaged. This damage leads to the many of the complications associated with sickle cell anemia.