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HomeHealth articleshemoglobin dWhat Is Hemoglobin D Type?

Hemoglobin D: Not a Disease

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Hemoglobin D is a variant trait of hemoglobin that is common and can be seen with no race and ethnicity discrimination. To know more, read the article.

Medically reviewed by

Dr. Abdul Aziz Khan

Published At September 5, 2023
Reviewed AtSeptember 5, 2023


Gene is the fundamental physical and functional component of heredity. Humans are determined by genetic makeup. Genes determine one’s emotions, functions, and conduct. Genes are the characteristics of the system, and they are the ones defining humans. Genes are composed of DNA, commanding human bodies on how to function. The children inherit genes equally from the mother and father. So, like hair, skin, and eye color, hemoglobin D is a form of hemoglobin that can be inherited from the parents to the children. It can occur in any race, sex, and ethnicity. But, it seems to prevail more among the East Indian descent.

What Is Hemoglobin D Type?

Hemoglobin is the predominant ingredient of red blood cells. Hemoglobin molecules are the one that helps blood carry oxygen and nutrients right from the lungs to various organs of the system. Hence, hemoglobin, the protein of red blood cells, plays a vital part in blood circulation. An individual inherits the hemoglobin from both of their parents. The person with the hemoglobin D trait has a normal hemoglobin called hemoglobin A and an abnormal (variant) one called hemoglobin D. The people with the hemoglobin D trait are considered carriers and have no health issues.

Hemoglobin D is often referred to as hemoglobin D Punjab or hemoglobin D Los Angeles. This distinct trait D is formed by the substitution of glutamine for the part of glutamic acid.

How Does Normal Hemoglobin Differ From Hemoglobin D Type?

Every person inherits two types of hemoglobin genes, one from each of their parents. So, genetic play decides the type of hemoglobin in humans. However, the standard hemoglobin and the distinct D trait differ in specific ways.

  • Red blood cells carrying normal hemoglobin are doughnut in shape, while red blood cells with hemoglobin D trait are smaller in size than the standard ones.

  • Normal hemoglobin concentration holds red blood cells of standard hemoglobin A. In contrast, the person with the hemoglobin D trait will have both hemoglobin A and hemoglobin D in the red blood cells.

How Is the Hemoglobin D Trait Inherited?

The exact cause of hemoglobin D is the mutation problem in the gene that generally codes for the beta-globin part of hemoglobin. So, this mutation leads to a change in the structure of hemoglobin, resulting in hemoglobin D formation.

Hemoglobin D trait is inherited from parents with a chance of 50 percent, in which one parent can have hemoglobin D and another parent with normal hemoglobin. So, the child could have a 50 percent possibility of hemoglobin D trait if the parent has hemoglobin D type. Studies show that hemoglobin D inherits with 1 in 2 chances of each pregnancy.

What Are the Possible Consequences of the Hemoglobin D Trait?

Hemoglobin D is never a disease and does not have any symptoms. In addition, people may have hemoglobin D type even without knowing it. Hemoglobin disorder is generally rare with this trait. People with the variant hemoglobin trait are not affected by hemoglobin D or sickle cell disease. And cannot develop these diseases in their later periods of life.

Nevertheless, they act as carriers by passing the hemoglobin D trait to the children. For instance, if both parents have an abnormal hemoglobin trait such as hemoglobin D, the child may have a hemoglobin disorder with a 25 percent possibility. Therefore, hemoglobin disorder resulting from the hemoglobin trait occurs in about one in four pregnancies. The hemoglobin disorder, in turn, is a serious, long-lasting disease culminating in severe health issues.

  • Hemoglobin D Disease: Hemoglobin D disease is a hemoglobinopathy that is known for a group of disorders resulting from abnormal synthesis, production, or structure of the hemoglobin component. Here, it is characterized by abnormal production of a variant called hemoglobin D. This condition has no or mild clinical manifestations, including mild anemia and splenomegaly. An increased hemoglobin D culminates in a decline in the number and size of red blood cells. Hence, a very mild anemic state results.

  • Hemoglobin SD Disease: Hemoglobin SD disease is a form of sickle cell disease. As the name indicates, hemoglobin SD disease possesses red blood cells containing both sickle hemoglobin and the D variant hemoglobin. In this disease, the form of hemoglobin D part influences the severity of the illnesses. The most severe type of hemoglobin SD disease is sickle hemoglobin with the D Punjab. This combination can lead to serious health problems.

  • Hemoglobin Thalassemia Disease: Hemoglobin D-beta zero thalassemia gets inherited with one in four possibilities of each pregnancy. It is similar to thalassemia disease but a life-long illness resulting in severe health problems.

How to Identify Hemoglobin D Trait?

Hemoglobin D does not indulge in serious health issues and illnesses, though. Parents with this particular trait might have children with specific hemoglobin D-related diseases such as hemoglobin D disease, hemoglobin D-beta thalassemia disease, and hemoglobin SD disease. So, it is essential to know whether the distinct trait is carried out. One must talk to healthcare professionals about hemoglobin D monitoring. Hemoglobin electrophoresis is a vital and primitive test generally recommended for the determination of the type of hemoglobin.

More Facts About Hemoglobin D:

  • A person with a hemoglobin D trait will always have them.

  • Hemoglobin D is not a disease to worry about. Subsequently, it can never progress into a disease or illness.

  • It is essential to monitor the hemoglobin trait status periodically for the wellness of the family.

  • Hemoglobin D does not lower the red blood cell count and hemoglobin concentration level. So, it is not a causative factor for anemia.

  • The D trait of hemoglobin will not induce any health problems.


It is critical to understand the hemoglobin status for one's own and future family's health. So, a simple blood test is the only means to see if one has the hemoglobin D trait. Moreover, it is not a disease to worry about but a marker or carrier to be concerned for. Therefore, one must talk to the healthcare provider about genetics and their testing if one or the family member has the hemoglobin D trait.

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Dr. Abdul Aziz Khan
Dr. Abdul Aziz Khan

Medical oncology


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