Hemoglobin E trait is a change (mutation) in a gene that affects hemoglobin in red blood cells. All red blood cells contain hemoglobin. Hemoglobin is a protein that carries oxygen from the lungs to all parts of the body.
People with normal hemoglobin have only one type, hemoglobin A. People with hemoglobin E trait have hemoglobin A and hemoglobin E in their red blood cells.
Most people with hemoglobin E trait have no signs or symptoms of illness. The trait normally does not cause any health problems.
People with hemoglobin E trait do not have hemoglobin E disease or hemoglobin E/beta thalassemia. They cannot develop the conditions later in life. But they can pass the genes for these diseases on to their children.
Hemoglobin E trait is rare. It is more common in people whose ancestors came from Southeast Asia, Africa, India, the Middle East, or the Mediterranean region. But it is possible for a person of any nationality or ancestry to have hemoglobin E trait.
A blood test can let you know if you have hemoglobin E trait. These tests are often done as part of routine newborn screening. Your doctor may also recommend the test if someone in your family has hemoglobin E trait.
Hemoglobin E trait runs in families. Like eye color or hair color, the genes for hemoglobin E trait are inherited, or passed from parents to children.
Parents who have hemoglobin E trait can have a child with hemoglobin E disease or hemoglobin E/beta thalassemia. Whether a child has the blood disorder depends on genes from both parents.
If one parent has hemoglobin E trait and the other parent has normal hemoglobin:
With each pregnancy, there is a 50% (1 in 2) chance of having a child with hemoglobin E trait.
These are the possible outcomes with each pregnancy:
If one parent has hemoglobin E trait and the other parent has beta thalassemia trait:
With each pregnancy, there is a 25% (1 in 4) chance of having a child with hemoglobin E/beta thalassemia disease, a lifelong blood disorder that requires medical treatment.
These are the possible outcomes with each pregnancy:
If both parents have hemoglobin E trait:
With each pregnancy, there is a 25% (1 in 4) chance of having a child with hemoglobin E disease.
These are the possible outcomes with each pregnancy:
To learn more about trait conditions, talk to your doctor or genetic counselor. Your care team can give you more details about your trait status and that of your child.
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Reviewed: December 2023
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