Thalassemias are blood disorders that affect the body’s ability to produce hemoglobin and red blood cells. Red blood cells transport oxygen throughout the body; hemoglobin is the protein in red blood cells that actually carries the oxygen.
People who have thalassemia produce fewer healthy hemoglobin proteins, and their bone marrow produces fewer healthy red blood cells. With too few normal red blood cells, not enough hemoglobin is available to help carry oxygen to the body.
Thalassemias can cause mild or severe anemia and other complications that can occur over time. Symptoms of anemia include fatigue, difficulty breathing, dizziness, and a pale skin tone.
Who is at risk for thalassemias?
Thalassemias occur more often among certain ethnicities, including people of Italian, Greek, Middle Eastern, Asian, and African descent. Thalassemias are an inherited disorder, which means they are passed from parents to their children.
What are the types of thalassemia?
Four protein chains make up hemoglobin—two alpha globin and two beta globin chains. There are two major types of thalassemia -- alpha thalassemia and beta thalassemia -- named after defects that can occur in these protein chains.
Four genes, two from each parent, are required to make alpha globin protein chains. When one or more genes are missing, it produces alpha thalassemia. This chart describes the different types of alpha thalassemia.
|Missing alpha genes ||Disorder ||Anemia symptoms ||Other names |
|1 ||silent carrier ||none ||Alpha thalassemia - 2 trait, alpha thalassemia minima |
|2 ||trait ||mild ||Alpha thalassemia - 1 trait, alpha thalassemia minor |
|3 ||Hemoglobin H ||moderate ||Hemoglobin H disease |
|4 ||major ||fatal ||Hydrops fetalis with Hemoglobin Barts |
What are the symptoms of alpha thalassemia?
People who are missing one alpha gene (silent carriers) usually don’t have any symptoms. Hemoglobin H disease often causes symptoms at birth and may cause moderate to severe lifelong anemia.
There are normally two beta globin genes, one from each parent. Beta thalassemia is a change in one or both of the beta globin genes. This chart describes the different types of beta thalassemia.
|Affected beta genes ||Disorder ||Anemia symptoms ||Other names |
|1 ||silent carrier ||mild ||Beta thalassemia minor |
|1 ||trait ||mild || |
|2 ||intermedia ||moderate || |
|2 ||major ||severe ||Cooley's anemia |
What are the symptoms of beta thalassemia?
Symptoms of beta thalassemia include growth problems, bone abnormalities such as osteoporosis, and an enlarged spleen (the organ in the abdomen that plays a part in fighting infection).
People who have thalassemias may suffer severe infections. One reason may be the large number of blood transfusions these patients need; the infections may be carried in the blood that they receive in a transfusion. Another reason is that patients with beta thalassemia sometimes have to have their spleens removed. Because the spleen helps fight infection, removing it places the person at risk for more infections.
How are thalassemias diagnosed?
Moderate and severe thalassemias are often diagnosed in childhood because symptoms usually appear during the first two years of a child’s life.
Various blood tests are used to diagnose thalassemias:
- A complete blood count (CBC), which includes measures of hemoglobin and the quantity (and size) of red blood cells. People with thalassemias have fewer healthy red blood cells and less hemoglobin than normal; those with alpha or beta thalassemia trait may have smaller-than-normal red blood cells.
- A reticulocyte count (a measure of young red blood cells) may indicate that your bone marrow is not producing an adequate number of red blood cells.
- Studies of iron will indicate whether the cause of the anemia is iron deficiency or thalassemia (iron deficiency is not the cause of anemia in people with thalassemias).
Genetic testing may be used to make a diagnosis when there is a family history of alpha thalassemia.
How are thalassemias treated?
Standard treatments for patients with thalassemia major are blood transfusions, iron chelation, removal of the spleen, and bone marrow transplant.
- Blood transfusion involves injection of red blood cells through a vein to restore normal levels of healthy red blood cells and hemoglobin. Transfusions are repeated every 4 months in patients with moderate or severe thalassemias, and every 2 to 4 weeks in patients with beta thalassemia major. Occasional transfusions may be needed (for instance, during times of infection) for hemoglobin H disease or beta thalassemia intermedia.
- Iron chelation is removal of excess iron from the body. A danger with blood transfusions is that they can cause iron overload, which may in turn cause heart disease. Because of this, patients who receive transfusions also require iron chelation therapy. One of two medicines is used for iron chelation: deferoxamine, a liquid given subcutaneously (under the skin), or deferasirox, a pill given by mouth. Patients who receive blood transfusions and iron chelation may have to take folic acid supplements to restore healthy red blood cells.
- Splenectomy (removal of the spleen) may be needed for patients with Hemoglobin H disease whose need for transfusions is increasing.
- Bone marrow transplant from a compatible related donor is the most effective treatment. Compatible means that the donor has the same types of proteins, called human leukocyte antigens (HLA), on the surface of their cells as the person who will be receiving the transplant. Bone marrow transplant from a compatible brother or sister offers the best chance at a cure. Most patients with thalassemia, however, lack a suitable sibling donor. A bone marrow transplant is done in the hospital. Within one month, the transplanted bone marrow stem cells will start to make new, healthy blood cells.
The patient may also need surgery to correct skeletal problems.
What is the prognosis (outlook) for patients with thalassemias?
Patients with moderate or severe thalassemias have a good chance of survival as long as they follow their treatment program (transfusions and iron chelation therapy). Heart disease from iron overload is the leading cause of death in patients with thalassemias, so keeping up with your iron chelation therapy is extremely important. A bone marrow transplant may cure thalassemia.
What kind of ongoing care will I need?
Frequent complete blood counts and blood iron tests will be necessary. Heart function and liver function tests are needed each year, as well as tests for viral infection (since having thalassemia increases your risk of certain serious infections). You also will need a yearly test for iron overload in your liver.
© Copyright 1995-2010 The Cleveland Clinic Foundation. All rights reserved.
Can't find the health information you’re looking for?
This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 4/15/2010…#14508