text: The links will give you more information. Here are two  brief overviews:\n\n   Sickle cell anemia is an inherited form of anemia — a condition in which there aren't enough healthy red blood cells to carry oxygen throughout your body.\n\nUnder normal circumstances, your red blood cells are flexible and round, and they move easily through your blood vessels to carry oxygen to all parts of your body. In people with sickle cell anemia, the red blood cells become rigid and sticky and are shaped like sickles or crescent moons. These irregular-shaped blood cells die prematurely, resulting in a chronic shortage of red blood cells. Plus, they can get stuck when traveling through small blood vessels, which can slow or block blood flow and oxygen to certain parts of the body. This produces pain and can lead to serious complications.\n\nThere's no cure for most people with sickle cell anemia. However, treatments can relieve pain and prevent further problems.\n\n-----------------------------------------------------\n\nSickle cell anemia is an inherited blood disorder characterized primarily by chronic anemia and periodic episodes of pain. The underlying problem involves hemoglobin, a component of red blood cells. Hemoglobin molecules in each red blood cell carry oxygen from the lungs to body organs and tissues and bring carbon dioxide back to the lungs. \n\nIn sickle cell anemia, the hemoglobin is defective. After hemoglobin molecules give up their oxygen, some may cluster together and form long, rod-like structures. These structures cause red blood cells to become stiff and assume a sickle shape. \n\nUnlike normal red cells, which are usually smooth and donut-shaped, sickled red cells cannot squeeze through small blood vessels. Instead, they stack up and cause blockages that deprive organs and tissues of oxygen-carrying blood. This process produces periodic episodes of pain and ultimately can damage tissues and vital organs and lead to other serious medical problems. Normal red blood cells live about 120 days in the bloodstream, but sickled red cells die after about 10 to 20 days. Because they cannot be replaced fast enough, the blood is chronically short of red blood cells, a condition called anemia.