Thalassemia is the name of a group of inherited blood disorders. Hemoglobin, the part of red blood cells that carries oxygen, is made up of two different proteins, called alpha and beta. If the body has an imbalance in the two proteins the red blood cells cannot carry enough oxygen.
Not enough alpha protein in the hemoglobin results in alpha thalassemia. It is commonly found in people from Africa, the Middle East, India, Southeast Asia, southern China, and sometimes from the Mediterranean. There are several different types of alpha thalassemia, ranging from mild to severe:
- Silent carrier state - only a small lack of alpha protein, so generally there are no health problems
- Alpha thalassemia trait or mild alpha thalassemia - lacking enough alpha protein to sometimes cause mild symptoms which are similar to iron deficiency anemia
- Hemoglobin H disease - enough alpha protein lacking to cause severe anemia and significant health problems such as bone deformities, enlarged spleen, and fatigue
- Alpha thalassemia major - no alpha protein is created by the body, so newborns with this thalassemia don't usually survive (they develop a disorder called fetal hydrops).
Not enough beta protein in the hemoglobin results in beta thalassemia. It is commonly found in people from Italy, Greece, Iran, Africa, Southeast Asia, and southern China. There are three main types of beta thalassemia, ranging from mild to severe:
- Thalassemia minor or thalassemia trait - only a small lack of beta protein, so generally there are no health problems except possibly mild anemia
- Thalassemia intermedia - enough beta protein lacking to cause moderately severe anemia and significant health problems such as bone deformities and enlarged spleen
- Thalassemia major or Cooley's anemia - no beta protein is created by the body, so regular blood transfusions and medical care are necessary.
Other forms of thalassemia
- E beta thalassemia - abnormal hemoglobin E combines with beta thalassemia to produce symptoms similar to beta thalassemia intermedia
- Sickle beta thalassemia - abnormal hemoglobin S combines with beta thalassemia. In its severe form it is like sickle cell disease.
Treatments and procedures
- Blood transfusions - most common treatment for all thalassemias; provides healthy red blood cells
- Chelation therapy - frequent blood transfusions cause iron to build up in the body. It has to be removed by medication before it causes damage to the heart and other organs.
- Splenectomy - if the spleen is enlarged or contributing to the thalassemia it may be removed
- Diet - Food rich in iron should be avoided. Vitamins C and E and folic acid are added as supplements.
- Bone marrow transplant - provides the only cure for thalassemia. However, there are many risks involved, so it is usually reserved for severe cases.
Research is looking at a number of ways to treat different types of thalassemia.
- In utero blood transfusion - Doctors give a baby a blood transfusion before birth to treat alpha thalassemia major.
- Gene therapy - Researchers are trying to figure out how to correct or modify flawed genes to decrease or cure different types of thalassemia.
- Hemoglobin F therapy - researchers have tried increasing the level of this type of hemoglobin but it has not had much effect on thalassemia.
- Protein therapy - A protein (AHSP) has been discovered that helps regulate the amount of alpha protein in red blood cells. Researchers are now looking at using AHSP as a thalassemia treatment.
Information for this article was taken from:
- Children's Hospital of Philadelphia. "Protein discovered that keeps hemoglobin in balance; research may advance treatment of the blood disease thalassemia." Press release, 6/13/02.
- Cooley's Anemia Foundation. What is Thalassemia?
- Yaish, H.M. (2001). Thalassemia. eMedicine, accessed at http://www.emedicine.com/ped/topic2229.htm