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Sickle Cell Disease

Source: MedlinePlus Health Topics, U.S. National Library of Medicine

Last synced 8/6/2026Status: primary verified

What is sickle cell disease (SCD)? Sickle cell disease (SCD) is a group of inherited red blood cell disorders. If you have SCD, there is a problem with your hemoglobin. Hemoglobin is a protein in red blood cells that carries oxygen throughout the body. With SCD, the hemoglobin forms into stiff rods within the red blood cells. This changes the shape of the red blood cells. The cells are supposed to be disc-shaped, but instead they are crescent, or sickle, shaped. The sickle-shaped cells are not flexible and cannot change shape easily. Many of them burst apart as they move through your blood vessels. The sickle cells usually only last 10 to 20 days, instead of the normal 90 to 120 days. Your body may have trouble making enough new cells to replace the ones that you lost. Because of this, you may not have enough red blood cells. This is a condition called anemia , and it can make you feel tired. The sickle-shaped cells can also stick to vessel walls, causing a blockage that slows or stops the flow of blood. When this happens, oxygen can't reach nearby tissues. The lack of oxygen can cause attacks of sudden, severe pain, called pain crises. These attacks can occur without warning. If you get one, you might need to go to the hospital for treatment. What causes sickle cell disease (SCD)? SCD is caused by a variant (change) in a gene that has instructions for your body to make one part of the hemoglobin. This changed gene is sometimes called a sickle cell gene. People with SCD are born with two sickle cell genes, one from each parent. If you are born with one sickle cell gene, it's called sickle cell trait. People with sickle cell trait are generally healthy, but they can pass the defective gene on to their children. Who is more likely to have sickle cell disease (SCD)? In the United States, most of the people with SCD are African Americans: About 1 in 13 Black or African American babies are born with sickle cell trait About 1 in every 365 Black or African American babies

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This information is for general education and is not medical advice. Always talk to a licensed U.S. clinician about your situation, medications, or treatment decisions.