The disease is inherited. People with sickle cell anemia inherit a sickle cell gene from each parent. People who inherit a sickle cell gene from only one parent have a condition called sickle cell trait. A person with sickle cell trait can pass on the gene to their children.

Red blood cells affected by sickle cell anemia are stiff, and because of their shape, they tend to get stuck in blood vessels. Sickle-cell blood cells also clump together, blocking the flow of blood and causing pain, organ damage, and infection.

Other forms include sickle beta-zero thalassemia and sickle-hemoglobin C disease.

Normal red blood cells do last about 120 days, but sickle cells last only 7 to 20 days. The bone marrow, which makes red blood cells, can't keep up with the rate that the sickle cell blood cells die. This leads to anemia—a lower than normal number of red blood cells in the body.

The disease occurs in about 1 in every 365 African-American babies, and in about 1 out of every 16,300 Hispanic-American infants. About 1 in 13 African Americans has sickle cell trait.

These crises are a common symptom of sickle cell disease. They occur when the sickle-shaped red blood cells clump together and block the flow of blood through small vessels called capillaries. The pain can range from mild to quite severe, and lasts several hours to a few days. Other common symptoms are severe tiredness (fatigue), pale skin, jaundice, dark urine, cold hands and feet, and shortness of breath—all symptoms of anemia.

Dehydration may bring on a sickle cell crisis. Other preventive tips:

• Try not to get really hot or really cold. Don't swim in cold water.
• Manage your stress.
• Don't fly in planes without a pressurized cabin.
• Get regular checkups. Call your healthcare provider right away if you have a fever or difficulty breathing.

The spleen's role is to filter out abnormal red blood cells from the body and fight infection. The spleen can be damaged by the disease because it may become so clogged with sickle cells that it can't do its job. A person with sickle cell anemia may have a hard time fighting off infection because of spleen damage. Common infections for a person with sickle cell anemia include pneumonia, flu (influenza), meningitis ,and hepatitis. Other complications of sickle cell anemia include delayed puberty in children, stroke, eye problems, gallstones, and high blood pressure in the lungs.

Sickle cell anemia is a lifelong disease. The only thing that may cure sickle cell anemia is a bone marrow or stem cell transplant. Not all people with sickle cell anemia are able to have a transplant. Other treatments are available to ease the pain and help prevent complications. Researchers are currently exploring gene therapy as a possible treatment, as well as new medicines for pain relief.