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How Do I Know If I Have Sickle Cell Trait?

Sickle cell disease runs in my family. I don’t have the disease, but I’m worried that I might carry the gene for the disease and pass it onto my children. How can I find out if I’m a carrier?
-Raiyah*

A simple blood test can tell if you’re a carrier of the sickle cell gene, called Hemoglobin S, or HbS.

Since sickle cell disease runs in your family, you are at risk of being a carrier — having what’s called “sickle cell trait.” African Americans are also at higher risk, with 1 in 12 carrying the gene. Others at higher risk include those from Middle Eastern, East Indian, or Mediterranean descent. Researchers theorize that these populations are most at risk because long ago the sickle cell gene may have provided protection against certain types of malaria, an illness that is common in those parts of the world.

If you get tested for sickle cell trait and find that you’re a carrier, it does not necessarily mean that your children will have the disease. They may inherit the gene from you, but in order to develop the disease their other parent needs to pass down the gene for sickle cell disease or another abnormal gene such as the one for B thalassemia or Hgb c, that when combined with a sickle cell gene can result in a child having a form of sickle cell disease. And even when both parents do, there’s still a chance that a child will not develop the disease.

Kids with two parents who have sickle cell trait have a 25% chance of developing the disease, while those with one parent who has sickle cell trait and one who has sickle cell disease have a 50% chance of sickle cell disease. These kids also have a risk of developing other blood-related disorders that are similar to sickle cell disease, like Hemoglobin S-C, C, E, and thalassemias.

Reviewed by: Robin E. Miller, MD
Date reviewed: August 2010