Sickle cell disease is a genetic blood disorder. That means it’s inherited. It’s marked by abnormally shaped red blood cells that can ultimately lead to severe attacks of pain. Doctors call these attacks “crises.”
It’s passed down through families. If your parents have the sickle cell trait, you may get sick from the disease, or you may only “carry” the gene and never have symptoms. Learning how the trait is inherited can help you better understand what to expect.
Sickle Cell Trait vs. Disease
Sickle cell disease (SCD) is the result of a broken hemoglobin gene. Hemoglobin is the substance that carries oxygen inside red blood cells. You need two copies of this defective gene -- one from each parent -- to develop sickle cell disease. (Doctors call this an autosomal recessive pattern of inheritance.) If both your parents have the problem gene, you have a 1-in-4 chance of being born with the disease.
People with sickle cell trait (SCT) also called have one normal hemoglobin gene and one abnormal hemoglobin gene. If both your parents carry the sickle cell trait, you have a 50% chance that only one of them will pass it on to you. If they do, you’ll have SCT.
People who carry the sickle cell trait aren’t likely to get sick with SCD symptoms. Sickle cell trait is not a mild form of sickle cell disease, and can never become sickle cell disease. But the trait may make you more likely to have get a certain type of kidney cancer and kidney disease, or have bloood in your urine (hematuria), and to possibly have an increased risk of blood clots. In addition, you may be more likely to have heat stroke or dangerous muscle breakdown after intense exercise. Athletes and those undergoing extreme military training should take extra precautions, such as drinking extra fluids and taking frequent breaks.
You can also pass the trait on to your children.
Who Has Sickle Cell Trait?
More than 100 million people across the world have it. About 1 in 13 African-Americans is born with the sickle cell trait. It’s also common in those whose ancestors are from:
- The Mediterranean
- The Middle East
- South Asia
Testing For the Trait
Your doctor can order a blood test to see if you carry the sickle cell trait.
Prenatal testing can tell if your baby has sickle cell disease or carries the sickle cell gene. Newborn screening programs require that every state in the U.S. test babies for SCD or the trait shortly after birth.