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What is Sickle Cell Trait?

Sickle cell disease is a genetic disorder that is passed down from parents to their children. The disease causes red blood cells (RBCs) to become crescent or “sickle” -shaped instead of round, making it difficult for them to pass through small blood vessels. When RBCs can’t get to the body’s organs, it can cause pain, damage to body organs, chronic anemia, infection, and other problems. Sickle cell is caused by a change or mutation in genes for the Beta chain of hemoglobin.

A child with sickle cell disease inherits genes for the disease from both parents. If only one parent has the gene for sickle cell disease and the other parent has a healthy gene, the child inherits just one gene for sickle cell disease. This is called sickle cell trait.

People with sickle cell trait don't have sickle cell disease or exhibit any signs of the disorder, but they can pass the gene for the disease to their children. If both parents have the sickle cell trait, there's a 25% chance that a child will have sickle cell disease. But when one parent is carrying the trait and the other actually has the disease, the odds increase to 50% that their child will inherit the disease.

Many people don't know they have sickle cell trait. A blood test can determine whether someone carries the sickle cell trait or has a form of the disease.

Date reviewed: February 2010