Top 5 Things to Know About Sickle Cell Disease

Sickle cell disease (SCD) is a group of inherited conditions affecting the protein inside our red blood cells that helps deliver oxygen throughout the body. This protein is called hemoglobin. Individuals with SCD have a variant that changes the shape of the red blood cells. Typically, the red blood cells are round and flexible, but in SCD, they are rigid and shaped like a sickle or a crescent moon. The beta globin gene can have variants, such as hemoglobin S, or sickle hemoglobin, that can lead to SCD or other blood disorders. Individuals affected by SCD have too few normal red blood cells (called long-lasting or chronic anemia) and may be at risk for stroke, eye problems, infections, and episodes of pain.

Individuals who have SCD have 2 non-working beta globin genes, one from each parent (called “autosomal recessive”). In all forms of SCD, at least 1 of the 2 copies of the gene causes a person’s body to make the variant called hemoglobin S. When a person has 2 hemoglobin S (Hb SS) variants, they have sickle cell anemia. This is the most common and often more severe type of SCD. Other types of SCD occur when 1 parent passes on a hemoglobin S variant, and the other parent passes on a beta-globin gene with a different variant, such as with Sickle SC disease or sickle-beta thalassemia. If a person has 1 hemoglobin S variant, they won’t have the condition but can pass it on to their children. This is called having sickle cell trait.

The signs and symptoms of SCD are caused by the red blood cells having a rigid and sickle shape. When the red blood cells become sickle-shaped, they break down too quickly, which can lead to a low number of red blood cells, also known as anemia. These misshapen red blood cells also don’t move very well through the small blood vessels in the body and can cause blockages. This may lead to pain, reduced oxygen flow to tissues and organs, and an increased risk of infection. The severity of symptoms can vary from person to person but usually begin in early childhood. SCD is a lifelong illness. 

According to the US National Institutes of Health and Centers for Disease Control and Prevention, SCD is the most common inherited blood disorder, affecting an estimated 100,000 Americans. SCD can affect people of all ethnic backgrounds but is more common among individuals with certain ancestries. In the US, approximately 1 in 13 Black Americans and about 1 in 100 Hispanic Americans have sickle cell trait and may be at increased risk to have children affected with SCD.

The American College of Obstetricians and Gynecologists (ACOG) recommends offering testing for hemoglobin conditions, including SCD, for everyone planning pregnancy or at the first prenatal visit. Screening may include a blood test to look at the red blood cells and hemoglobin protein, as well as genetic testing to tell if you are a carrier for SCD and other hemoglobin conditions. Couples found to be at an increased risk to have a child with SCD can consider prenatal testing to find out if the baby will be affected. In addition to screening and prenatal testing for SCD, all states in the US screen newborns for SCD as part of their newborn screening programs.