Hemoglobinopathy and Sickle Cell Anemia: Overview

What is a hemoglobinopathy?

Hemoglobin is the protein in red blood cells that carries oxygen. Oxygen is important to sustain the body's tissues and cells.

Normal hemoglobin is called "Hemoglobin A." Most people have AA hemoglobin, meaning they have two normal copies of the hemoglobin gene.

There are about 500 different types of hemoglobins, called variants. Most variant hemoglobins do not cause any problems. However, a few cause severe medical problems. People who have two variant hemoglobins have a condition called a "hemoglobinopathy."

What is sickle cell anemia and sickle cell disease?

The most common variant (different type) hemoglobin is S or sickle. When individuals have SS hemoglobin, it causes the red blood cell to form a crescent shape instead of the normal disk shape. If someone has two S hemoglobins, they have sickle cell anemia.

Some people will have one S and one C hemoglobin, which causes SC sickle cell disease.

If a person has one S hemoglobin and thalassemia, this causes sickle cell thalassemia disease.

What does sickle cell anemia do to the body?

If a person has sickle cell anemia or disease, there are many complications that can occur. In children with sickle cell anemia, the crescent-shaped red blood cell is not able to deliver as much oxygen as needed to the body – which can cause episodes of pain because of the condition.

What is thalassemia?

Other individuals may have thalassemia, a condition where the body does not make enough hemoglobin.

People with thalassemia who cannot make any normal hemoglobin have "beta thalassemia major." People who make less hemoglobin A than normal have "beta thalassemia trait." Both groups can have medical problems.

There are also other types of thalassemias caused by variant hemoglobins such as E, D and others.

What causes hemoglobinopathy and who gets it?

Variant hemoglobin is inherited from a parent, although the parent may not know he or she has it. People from any race or sex may have abnormal hemoglobin.