Thalassemia; Mediterranean anemia; Cooley’s anemia
Thalassemias are hereditary disorders characterized by defective production of hemoglobin. This leads to low production, and over destruction, of red blood cells.
Causes, incidence, and risk factors
Hemoglobin contains two chains, alpha and beta globin. Genetic defects can be inherited that cause imbalances in the production of either chain.
Beta thalassemias are caused by a mutation in the beta globin chain. Genes must be inherited from both parents to acquire the major form of the disease. If one gene is inherited, the person will be a carrier of the disease, but will not have symptoms. (This is the minor form.)
In the major form, children are normal at birth, but develop anemia during the first year of life. Growth failure, bone deformities, and enlarged liver and spleen are some of the problems that can occur. Blood transfusions may modify some of the disease manifestation, but iron overload from the transfusions can cause damage to the heart, liver, and endocrine systems.
The mild form of beta thalassemia produces small red blood cells, with no symptoms. Risk factors include a family history of thalassemia and an ethnic background susceptible to the disease.
Beta thalassemias occur in people of Mediterranean origin, and to a lesser extent, Chinese, other Asians, and blacks
Alpha thalassemias occur most commonly in people from southeast Asia and China, and are caused by deletion of a gene or genes from the globin chain. The most severe form of alpha thalassemia causes a stillborn fetus.
- Shortness of breath
- Bone deformities in the face
Signs and tests
- Enlarged spleen
- Peripheralblood smear shows small, abnormally-shaped red blood cells
- Complete blood count shows anemia
- Hemoglobin electrophoresis shows abnormal hemoglobin
This disease may also alter the results of the following tests:
- RBC indices (size, hemoglobin content)
- Osmotic fragility
With severe thalassemia, regular blood transfusions and folate supplementation are given. People who receive the blood transfusions should avoid iron supplements and oxidative drugs such as sulfonamides, because iron levels can become toxic.
Patients who receive significant numbers of blood transfusions require therapy to remove iron from the body, called chelation therapy. Bone marrow transplant is being investigated as a treatment and is most successful in children.
In severe thalassemia, death from heart failure can occur between the ages or 20 and 30. Hypertransfusion programs with chelation therapy improve outcome, and successful bone marrow transplantation is curative. Less severe forms of thalassemia usually do not impact on life span.
Untreated, thalassemia major leads to heart failure as well as liver dysfunction, and susceptibility to infection.
Iron overload as a side effect of treatment can cause damage to the heart, liver, and endocrine systems. This complication is managed by daily injections of an iron chelating agent which binds iron to it and causes it to be excreted in the urine.
Calling your health care provider
Call for an appointment with your health care provider if symptoms develop that are suggestive of thalassemia.
Call your health care provider if symptoms develop after treatment.
- Genetic counseling in families with known thalassemia
- Prenatal screening
by Amalia K. Gagarina, M.S., R.D.