Skip to Main Content

Welcome to

Together is a new resource for anyone affected by pediatric cancer - patients and their parents, family members, and friends.

Learn More
Blog Community

Hemoglobin D Trait

What is hemoglobin D trait?

Hemoglobin D trait is a change (mutation) in a gene that helps make 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 D trait have hemoglobin A and hemoglobin D in their red blood cells.

A trait is different from a disease

Most people with hemoglobin D trait have no signs or symptoms of illness. The trait normally does not cause any health problems.

People with hemoglobin D trait do not have hemoglobin D disease or hemoglobin SD disease. They cannot develop the conditions later in life. But they can pass the genes for the diseases on to their children.

  • Hemoglobin D disease is an inherited blood disorder that causes a person to have red blood cells that contain mostly hemoglobin D. Too much hemoglobin D can reduce the number and size of red blood cells in your body, causing mild anemia. Hemoglobin D disease is not a form of sickle cell disease and usually does not cause serious health problems.
  • Hemoglobin SD disease is a type of sickle cell disease. People who have Hemoglobin SD disease (also called sickle SD disease) have red blood cells that contain both hemoglobin S and hemoglobin D. Some types of hemoglobin SD disease can cause serious health problems. The severity of the disease depends on the type of hemoglobin D.

Risk factors for hemoglobin D trait

Hemoglobin D trait is more common in people whose ancestors came from India or people of Asiatic Indian heritage. But it is possible for a person of any nationality or ancestry to have hemoglobin E trait.

Tests for hemoglobin D trait

A simple blood test can let you know if you have hemoglobin D trait. These tests are often done as part of routine newborn screening. Your doctor may suggest the test if someone in your family has hemoglobin D trait.

How hemoglobin D trait is inherited

Hemoglobin D trait runs in families. Like eye color or hair color, the genes for hemoglobin D trait are inherited, or passed from parents to children.

Parents who have hemoglobin D trait can have a child with hemoglobin D disease, hemoglobin SD disease, or hemoglobin D/beta thalassemia disease.

Whether a child has the disease depends on genes from both parents. It is important to understand how hemoglobin C trait is passed on and how it can affect the health of your children and grandchildren.

Hemoglobin D trait and Normal No Trait parents

If one parent has hemoglobin D 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 D trait.

These are the possible outcomes with each pregnancy:

  • 50% (1 in 2) chance of having a child with hemoglobin D trait
  • 50% (1 in 2) chance of having a child without hemoglobin D trait
 
Both parents with Hemoglobin D Trait

If both parents have hemoglobin D trait:

With each pregnancy, there is a 25% (1 in 4) chance of having a child with hemoglobin D disease.

These are the possible outcomes with each pregnancy:

  • 25% (1 in 4) chance of having a child with hemoglobin D disease
  • 50% (1 in 2) chance of having a child with hemoglobin D trait
  • 25% (1 in 4) chance of having a child without trait or disease
 
One parent with hemoglobin D trait and other parent with sickle cell trait

If one parent has hemoglobin D trait and the other parent has sickle cell trait:

With each pregnancy, there is a 25% (1 in 4) chance of having a child with hemoglobin SD disease, a type of sickle cell disease.

People who have hemoglobin SD disease have red blood cells that contain both hemoglobin S and hemoglobin D. Hemoglobin SD disease is a lifelong illness that can cause serious health problems. People with the disease need medical treatment.

These are the possible outcomes with each pregnancy:

  • 25% (1 in 4) chance of having a child with hemoglobin D trait
  • 25% (1 in 4) chance of having a child with sickle cell trait
  • 25% (1 in 4) chance of having a child with hemoglobin SD disease (sickle cell disease)
  • 25% (1 in 4) chance of having a child without trait or disease
 
One parent with hemoglobin D trait and the other parent with Beta Thalassemia trait

If one parent has hemoglobin D trait and the other parent has beta thalassemia trait:

With each pregnancy, there is a 25% (1 in 4) chance with each pregnancy of having a child with hemoglobin D/beta zero thalassemia (Dβ0) disease. Hemoglobin Dβ0 disease is a lifelong illness that can result in serious health problems.

These are the possible outcomes with each pregnancy:

  • 25% (1 in 4) chance of having a child with hemoglobin D trait
  • 25% (1 in 4) chance of having a child with beta thalassemia trait
  • 25% (1 in 4) chance of having a child with hemoglobin D/beta zero thalassemia disease
  • 25% (1 in 4) chance of having a child without trait or disease
 

To learn more about hemoglobin D trait, talk to your doctor or genetic counselor. Your care team can give more details about your trait status and that of your child.

Key points about hemoglobin D trait

  • Hemoglobin D trait is inherited or passed down from parents to children, like hair or eye color.
  • People with hemoglobin D trait have both normal hemoglobin A and abnormal hemoglobin D in their red blood cells.
  • Having hemoglobin D trait does not cause any health problems.
  • A simple blood test can let you know if you have hemoglobin D trait.
  • Parents who have hemoglobin D trait can have a child with hemoglobin D disease, hemoglobin SD disease, or hemoglobin D/beta zero thalassemia disease.


Reviewed: December 2023