What is beta thalassemia?
Beta thalassemia is a type of thalassemia that is inherited (passed down through families). It is a blood disorder that reduces the production of healthy red blood cells and normal hemoglobin. Hemoglobin is an iron-rich protein in red blood cells that carries oxygen to cells throughout the body. There are two parts of this protein – one is called alpha globin and one is called beta globin.
Certain genes control how the body makes hemoglobin. When these genes are altered (changed) or missing, thalassemia occurs. The specific hemoglobin protein affected in beta thalassemia is the beta globin.
People who inherit faulty hemoglobin genes from one parent but normal genes from the other are called carriers. Although carriers of beta thalassemia usually have no signs or symptoms. However, they can pass the faulty genes on to their children. People who have moderate to severe forms of beta thalassemia have inherited faulty hemoglobin genes from both parents.
Beta globin is made by two specific genes—one on each strand of chromosome 11. Each person needs these two genes (one from each parent) to make enough beta globin for the body’s hemoglobin to work normally. Different forms of beta thalassemia occur if one or more of these genes are altered:
- If one gene is altered—a person is a “silent” carrier of beta thalassemia. This condition is called beta thalassemia trait (also called beta thalassemia minor) and can cause mild anemia.
- If both genes are altered—a person has beta thalassemia intermedia or beta thalassemia major (also called Cooley’s anemia). The middle form of the disorder causes moderate anemia and the major form causes severe anemia.
How common is beta thalassemia?
Because beta thalassemia is inherited, family history and ancestry can help diagnose this blood disorder.
If one parent has beta thalassemia trait, and the other parent does not, there is a 50% chance of a child having beta thalassemia trait.
If both parents have beta thalassemia trait, there is a 25% chance of having a child with beta thalassemia intermedia or major.
Beta thalassemia can combine with other altered beta genes and cause problems also. For example, if one parent has beta thalassemia trait and the other parent has sickle cell trait (another type of altered beta globin gene), there is a 25% chance of having a child with sickle beta thalassemia disease. People with sickle beta thalassemia disease can have health issues ranging from moderate to severe depending on the type of beta thalassemia inherited.
Beta thalassemia is one of the most common blood disorders in the world. Thousands of infants are born with the disorder each year. Anyone can have beta thalassemia, but it is most common in Southeast Asia. Beta thalassemia also occurs often in people of African, Greek, Italian and Middle Eastern descent.
What are the signs and symptoms of beta thalassemia?
Signs and symptoms of beta thalassemia are caused by a lack of oxygen in the bloodstream. This occurs because the body does not make enough healthy red blood cells and beta globin.
The severity of signs or symptoms depends on the type of beta thalassemia a person has and the severity of the disorder:
- Mild anemia or no signs or symptoms—Many people with beta thalassemia trait have no signs or symptoms of the disorder. However, they can have mild anemia. Symptoms include:
- Feeling tired or weak (fatigue)
- Shortness of breath
- Feeling dizzy
- Cold hands and feet
- Pale skin
- Chest pain
- Mild to moderate anemia and other health problems—People with beta thalassemia intermedia have mild to moderate anemia and may also have other health issues:
- Slowed growth and delayed puberty
- Enlarged spleen
- Bone problems
- Severe anemia and other health problems—People with beta thalassemia major have severe anemia and may also have other health issues:
- Pale skin and listless
- Poor appetite
- Dark urine
- Yellowish skin or whites of the eyes (jaundice)
- Slowed growth and delayed puberty
- Enlarged spleen, liver or heart
- Bone problems
How is beta thalassemia treated?
Treatment for beta thalassemia is based on the type and severity of the disorder. People who have beta thalassemia trait usually have mild or no symptoms and need little or no treatment. Three standard treatments are used for moderate and severe forms of the disorder:
- Blood transfusions—are the main treatment for people with moderate or severe beta thalassemia. This treatment provides healthy red blood cells with normal hemoglobin.
- Because red blood cells only live about three months, repeated transfusions may be needed to maintain a healthy supply of red blood cells.
- People with beta thalassemia intermedia may need a blood transfusion on occasion, such during an infection or other illness, or if symptoms of anemia occur.
- People with beta thalassemia major may need regular blood transfusions every four to six weeks. Blood transfusions are a life-saving treatment that can help people with severe beta thalassemia feel better, live longer and have better quality of life overall. However, they increase the risk of transmitted infections and viruses such as hepatitis. Careful blood screening is practiced in the United States, which makes this risk much lower.
- Iron chelation therapy—removes excess iron from the body often caused by repeated blood transfusions, which are a treatment for moderate or severe beta thalassemia. Buildup of iron in the blood (iron overload) can damage the heart, liver and other parts of the body.
Two drugs are used for chelation therapy:
- Deferoxamine—a liquid medicine given slowly under the skin, usually overnight, five to six nights a week, with a small portable pump. This treatment takes time and can be mildly painful. Side effects may include problems with hearing and vision.
- Deferasirox—an oral drug taken by mouth once a day. Side effects may include headache, nausea, vomiting, diarrhea, tiredness and joint pain.
Used much less often, these other treatments for beta thalassemia exist or are being explored:
- Blood and bone marrow stem cell transplant—replaces faulty stem cells with healthy ones from a donor.
- Stem cells are the cells inside bone marrow that become red blood cells and other types of blood cells.
- A stem cell transplant is the only treatment that can cure beta thalassemia, but the procedure is risky.
- Only a small percentage of people with severe beta thalassemia are able to be matched well with a donor.
- Future treatments—Researchers are working to find possible new treatments for beta thalassemia.
- By using gene therapy, someday it might be possible for doctors to insert a normal hemoglobin gene into stem cells in bone marrow. This might allow people with beta thalassemia to make their own healthy hemoglobin and red blood cells.
- Scientists are studying ways to trigger the body’s ability to make fetal hemoglobin after birth. The body switches to making adult hemoglobin when a baby is born. So, making more fetal hemoglobin might help replace the lack of healthy adult hemoglobin in people with beta thalassemia.
What are the survival rates for beta thalassemia?
Treatment for beta thalassemia has improved, and people with moderate or severe forms of the disorder are living longer with better quality of life. However, health problems caused by beta thalassemia and its treatment are common and can be serious.
Severe beta thalassemia can cause heart failure and death, most often between the ages of 20 and 30. Regular blood transfusions and iron chelation therapy may help improve chances of survival.
Less severe forms of beta thalassemia usually do not shorten the person’s lifespan.
Genetic counseling and prenatal screening may help people with a family history of beta thalassemia who plan to have children.
Why choose St. Jude for your child’s beta thalassemia treatment?
- The nurse-to-patient ratio at St. Jude is unmatched—averaging 1:3 in hematology and oncology, and 1:1 in the Intensive Care Unit.
- The hospital’s major treatment programs are so successful because the doctors and laboratory scientists work closely together to quickly develop new therapies.
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