Thalassemia is an inherited (i.e., passed from parents to children through genes) blood disorder caused when the body doesn’t make enough of a protein called hemoglobin, an important part of red blood cells. When there isn’t enough hemoglobin, the body's red blood cells don’t function properly and they last shorter periods of time, so there are fewer healthy red blood cells traveling in the bloodstream.
Red blood cells carry oxygen to all the cells of the body. Oxygen is a sort of food that cells use to function. When there are not enough healthy red blood cells, there is also not enough oxygen delivered to all the other cells of the body, which may cause a person to feel tired, weak or short of breath. This is a condition called anemia. People with thalassemia may have mild or severe anemia. Severe anemia can damage organs and lead to death.
What are the different types of thalassemia?
When we talk about different “types” of thalassemia, we might be talking about one of two things: the specific part of hemoglobin that is affected (usually either “alpha” or “beta”), or the severity of thalassemia, which is noted by words like trait, carrier, intermedia, or major.
Hemoglobin, which carries oxygen to all cells in the body, is made of two different parts, called alpha and beta. When thalassemia is called “alpha” or “beta,” this refers to the part of hemoglobin that isn’t being made. If either the alpha or beta part is not made, there aren’t enough building blocks to make normal amounts of hemoglobin. Low alpha is called alpha thalassemia. Low beta is called beta thalassemia.
When the words “trait,” “minor,” “intermedia,” or “major” are used, these words describe how severe the thalassemia is. A person who has thalassemia trait may not have any symptoms at all or may have only mild anemia, while a person with thalassemia major may have severe symptoms and may need regular blood transfusions.
In the same way that traits for hair color and body structure are passed down from parents to children, thalassemia traits are passed from parents to children. The type of thalassemia that a person has depends on how many and what type of traits for thalassemia a person has inherited, or received from their parents. For instance, if a person receives a beta thalassemia trait from his father and another from his mother, he will have beta thalassemia major. If a person received an alpha thalassemia trait from her mother and the normal alpha parts from her father, she would have alpha thalassemia trait (also called alpha thalassemia minor). Having a thalassemia trait means that you may not have any symptoms, but you might pass that trait on to your children and increase their risk for having thalassemia.
Sometimes, thalassemias have other names, like Constant Spring, Cooley’s Anemia, or hemoglobin Bart hydrops fetalis. These names are specific to certain thalassemias – for instance, Cooley’s Anemia is the same thing as beta thalassemia major.
How do I know if I have thalassemia?
People with moderate and severe forms of thalassemia usually find out about their condition in childhood, since they have symptoms of severe anemia early in life. People with less severe forms of thalassemia may only find out because they are having symptoms of anemia, or maybe because a doctor finds anemia on a routine blood test or a test done for another reason.
Because thalassemias are inherited, the condition sometimes runs in families. Some people find out about their thalassemia because they have relatives with a similar condition.
People who have family members from certain parts of the world have a higher risk for having thalassemia. Traits for thalassemia are more common in people from Mediterranean countries, like Greece and Turkey, and in people from Asia, Africa, and the Middle East. If you have anemia and you also have family members from these areas, your doctor might test your blood further to find out if you have thalassemia.
How can I prevent thalassemia?
Because thalassemia is passed from parents to children, it is very hard to prevent. However, if you or your partner knows of family members with thalassemia, or if you both have family members from places in the world where thalassemia is common, you can speak to a genetic counselor (go to: http://nsgc.org/p/cm/ld/fid=164 ?) to determine what your risk would be of passing thalassemia to your children.
- Centers for Disease Control and Prevention
National Center on Birth Defects and Developmental Disabilities
Division of Blood Disorders
1600 Clifton Road
Atlanta, GA 30333
TTY: (888) 232-6348
- Contact CDC-INFO