Sickle Cell Trait

What Is Sickle Cell Trait?

Sickle cell trait is a blood condition that gets passed down through some families in their genes. It can’t turn into sickle cell disease and it doesn’t usually cause health problems.

A person has sickle cell trait when they inherit a copy of the “sickle cell gene” from one of their parents. With only 1 copy of the sickle cell gene, they don’t have sickle cell disease, but they can pass a copy of the gene on.A person with sickle cell trait is also called a “carrier.”

How Do Sickle Cell Trait and Sickle Cell Disease Differ?

Sickle cell trait doesn’t usually cause health problems. Symptoms are rare and usually can be prevented.

Sickle cell disease is a blood disorder where red blood cells are curved instead of round. The curved cells can get stuck in and block small blood vessels. Blood can't flow normally, which can lead to pain and organ damage. People with sickle cell disease need lifelong medical care.

How Does Someone Get Sickle Cell Trait?

To understand how someone gets sickle cell trait, it helps to know about the beta-globin gene.

Everybody has 2 copies of the beta-globin gene that they inherit, one from each parent. Beta-globin genes tell the body how to make hemoglobin (HEE-muh-glow-bin), a protein in red blood cells that carries oxygen. One type of beta-globin gene that someone can inherit is called the sickle beta-globin gene, or “sickle cell gene” for short.

A person gets sickle cell trait by inheriting a normal beta-globin gene from one parent and a sickle beta-globin gene (sickle cell gene) from the other parent.

A genetic counselor can explain how sickle cell trait, sickle cell disease, and other blood disorders can run in families.

What Are the Signs & Symptoms of Sickle Cell Trait?

Most people with sickle cell trait don’t have the problems that can happen with sickle cell disease. That's because their normal copy of the beta-globin gene lets their bodies make enough normal hemoglobin.

Rarely, though, a person with sickle cell trait may have:

• pain if they spend time at high altitudes
• muscle breakdown if they exercise very hard
• glaucoma after an eye injury
• blood in the urine (hematuria)

A person with sickle cell trait who has any of these symptoms should talk to their doctor.

How Is Sickle Cell Trait Diagnosed?

To diagnose sickle cell trait, doctors use a blood test called hemoglobin electrophoresis (eh-lek-truh-fer-EE-sis).

In the United States, every newborn baby gets this test as part of newborn screening. Many other countries routinely test newborns too. A newborn screening can tell if a baby has sickle cell trait, sickle cell disease, or another problem with their hemoglobin.

People who don’t know their status can ask their doctor for a hemoglobin electrophoresis test. Sometimes, pregnant women who don’t know if they have sickle cell trait will get the test. This lets them know their baby's chances of having a hemoglobin problem.

How Can Parents Help?

If your child has sickle cell trait:

• Take them to all their checkups.
• Tell all health care providers that your child has sickle cell trait.
• Encourage your child to drink plenty of water, especially when exercising or in hot weather.
• Help them stay active safely. They should pace themselves and take breaks when they’re tired or feel weak. Kids who play sports should exercise safely and build up intensity slowly.
• Teach your child how sickle cell trait is inherited. Knowing this health information will help them make decisions before they plan a family of their own.

You can learn more about sickle cell trait online at:

• The CDC