Sickle Cell Trait

Topic Overview

What is sickle cell trait?

Sickle cell trait occurs when a person inherits a sickle cell gene from just one parent. It's not the same as sickle cell disease, in which a person inherits two sickle cell genes, one from each parent.

People with sickle cell disease have just one kind of hemoglobin(hemoglobin S), which turns their normal, round red blood cells into abnormally curved (sickle) shapes. But people with sickle cell trait have both normal hemoglobin (hemoglobin A) and hemoglobin S, so they rarely have symptoms of sickle cell disease. But they are carriers and can pass the sickle cell gene to their children.

How is sickle cell trait diagnosed?

A simple blood test can show whether you have sickle cell trait. During pregnancy, a woman can have a test to find out if the baby will have either sickle cell disease or sickle cell trait. In the United States, most states test for sickle cell status at birth. Some college athletic programs screen student athletes to find out if they have sickle cell trait.

What does it mean to test positive for sickle cell trait?

People with sickle cell trait rarely have symptoms. Testing positive for sickle cell trait doesn't mean that you need to have treatment or make changes in your activities.

But in rare cases, a person with sickle cell trait may have muscle pain or other serious health problems. These problems can happen under certain extreme conditions, such as intense exercise, overheating, or being at a high altitude.

If you exercise intensely or are a competitive athlete, you can take precautions to help prevent complications:^{footnote 1}

• Drink plenty of fluids, especially during intense activities.
• Increase your level of performance gradually.
• Stop right away if you feel muscle pain, weakness, fatigue, or breathlessness.

Work with your doctor and coaches to create a plan to prevent complications. Know what to do if you have problems.

Does sickle cell trait affect pregnancy?

Women who have sickle cell trait can have a healthy pregnancy.

If you or your partner has sickle cell trait, you may want to talk with a genetic counselor before getting pregnant. A genetic counselor can help you learn more about your chances of having a child with sickle cell disease.

A person with sickle cell trait has a 1-in-2 (50%) chance of passing the sickle cell trait gene to each of his or her children. If both parents have sickle cell trait, each of their children will have a 1-in-4 (25%) chance of having sickle cell disease.