Thalassemia is a group of inherited blood diseases that affect a person's ability to produce hemoglobin in red blood cells. A person with thalassemia does not have enough hemoglobin or red blood cells to carry oxygen throughout the body, which can cause mild to severe anemia.
Approximately 100,000 babies worldwide are born with severe forms of thalassemia each year. The condition occurs more frequently in people of Italian, Greek, Middle Eastern, Southern Asian, and African ancestry.
Thalassemia occurs when the genes that code for hemoglobin are missing or variant (different from normal genes). Severe forms of thalassemia are usually diagnosed in early childhood and are considered lifelong conditions.
Genetics and Types of Thalassemia
The two main types of thalassemia, alpha and beta, are named for the two protein chains that make up normal hemoglobin. Both types of thalassemia are passed from parents to their children.
There are mild and severe forms of thalassemia as well. Severe thalassemia is often called Cooley's anemia, which is the most common severe form of thalassemia seen in the United States.
(Click Cooley's Anemia for more information about this severe form of anemia.)
Alpha thalassemia occurs when one or more of the four genes needed for making the alpha-globin chain of hemoglobin are variant or missing. Moderate to severe anemia will result when more than two genes are affected.
Beta thalassemia occurs when one or both of the two genes needed for making the beta-globin chain of hemoglobin are variant. If both genes are affected, anemia can range from moderate to severe.
Some people are "silent carriers" of thalassemia and do not have any symptoms. Other carriers (also known as thalassemia trait) have mild anemia, but they usually do not need treatment. However, carriers can pass thalassemia genes on to their children.
Common Symptoms of Thalassemia
The symptoms of thalassemia will depend on the type and severity of the disease. Symptoms generally occur when oxygen does not get to various parts of the body due to low hemoglobin and a shortage of red blood cells in the blood (anemia).
Doctors typically diagnose thalassemia after conducting blood tests, including a complete blood count (CBC) and special hemoglobin studies.
A CBC provides information about the amount of hemoglobin in the blood and the different kinds of blood cells in the blood. People with thalassemia have less hemoglobin than normal and fewer red blood cells than normal in their blood. Carriers of the thalassemia trait may have slightly fewer red blood cells than normal in their blood.
Hemoglobin studies measure the types of hemoglobin in a blood sample.
Current Treatment for Thalassemia
Treatment for thalassemia will depend on the type and severity of the disease. Examples include:
- People who are carriers of the thalassemia trait usually have no symptoms and need no treatment.
- People with moderate forms of thalassemia may need occassional blood transfusions.
- People with severe thalassemia have a serious and life-threatening illness. They are treated regularly with blood transfusions, iron chelation therapy, and bone marrow transplants. Without treatment, children with severe thalassemia will not live beyond early childhood.
Bone marrow or stem cell transplants have cured thalassemia in some children. However, this treatment is not available for most people with the condition.
Thalassemia research scientists are studying new treatments for thalassemia, including ways to cure the disease through stem cell and gene therapies.
Other Names for Thalassemia
Other names for alpha thalassemia include:
- Alpha thalassemia "silent carrier"
- Mild alpha thalassemia (also called alpha thalassemia minor or alpha thalassemia trait)
- Hemoglobin H disease
- Hydrops fetalis or alpha thalassemia major.
- Beta thalassemia minor (also called thalassemia minor or thalassemia trait)
- Beta thalassemia intermedia (also called thalassemia intermedia or mild Cooley's anemia)
- Beta thalassemia major (also called thalassemia major or Cooley's anemia)
- Mediterranean anemia.
The term "Cooley's anemia" is sometimes used to refer to any type of thalassemia that requires treatment with regular blood transfusions.
Key information to keep in mind regarding thalassemia includes:
- Thalassemia is a group of inherited blood disorders that can cause mild to severe anemia.
- The condition involves problems with the production of hemoglobin in red blood cells. As a result, a person with thalassemia does not have enough hemoglobin or red blood cells to carry oxygen throughout the body.
- There are two main types of thalassemia: alpha and beta thalassemia. Alpha thalassemia occurs when there is a problem with the alpha-globin chain that is part of hemoglobin. Beta thalassemia occurs when there is a problem with the beta-globin chain.
- There are mild, moderate, and severe forms of thalassemia. The most common severe form seen in the United States is beta thalassemia major (Cooley's anemia).
- Thalassemia mainly affects people from Mediterranean countries and Asia.
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