Sickle Cell Disease Inheritance Patterns and Trait

Sickle cell disease patients are born with the condition. Sickle cell disease is caused by two abnormal genes, one from each parent. Your or your child’s specific type of sickle cell disease depends on which genes were inherited.

As this sickle cell disease inheritance patterns flowchart illustrates, each parent has one hemoglobin A gene and one hemoglobin S gene, meaning each child of these parents has:

  • a 25% chance of inheriting two normal genes (the child does not have sickle cell trait or disease)
  • a 50% chance of inheriting one hemoglobin A gene and one hemoglobin S gene (the child has sickle cell trait)
  • 25% percent chance of inheriting two hemoglobin S genes (the child has sickle cell disease)

Sickle Cell Trait

Sickle cell trait occurs when a child inherits a sickle cell gene from one parent and a normal hemoglobin gene from the other. Children with one sickle cell gene are carriers of sickle cell disease and have sickle cell trait. While they can pass the trait along to their children, sickle cell trait is not typically considered a disease.

 If you or your child has sickle cell trait, you won’t generally experience any related health problems; however, you should be aware of some potential rare complications associated with this condition.

Practice increased caution in low-oxygen situations, such as during strenuous exercise or breathing in places with high altitudes. Decreased oxygen to your body tissue can cause your red blood cells to sickle, potentially resulting in organ damage and other complications. The NCAA has some great resources for athletes with Sickle Cell Trait.

People with sickle cell trait have a 50% chance of passing the trait along to each of their kids. If you are a carrier of sickle cell trait, find out your partner’s carrier status. Your future children will be at risk for developing sickle cell disease if your partner has sickle cell trait, sickle cell disease, or any other hemoglobin disorder.  

Call the IHTC for more information about genetic counseling and testing.

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