What is thalassemia?
Thalassemia (thal-uh-SEE-me-uh) is an inherited blood disorder. It affects your body’s ability to produce normal hemoglobin. Hemoglobin is a protein in red blood cells. It allows your red blood cells to transport oxygen throughout your body, nourishing your body’s other cells.
If you have thalassemia, your body produces fewer healthy hemoglobin proteins, and your bone marrow produces fewer healthy red blood cells. The condition of having fewer red blood cells is called anemia. As red blood cells serve the vital role of delivering oxygen to tissues in your body, not having enough healthy red blood cells can deprive your body’s cells of the oxygen they need to make energy and thrive.
How does thalassemia affect my body?
Thalassemia can cause mild or severe anemia and other complications over time (such as iron overload). Symptoms of anemia include:
- Trouble breathing.
- Feeling cold.
- Pale skin.
Who is at risk for thalassemia?
The gene mutations that cause thalassemia arose in humanity as partial protections against malaria. So, thalassemia affects people who have ancestral links to parts of the world where malaria is prevalent, such as Africa, Southern Europe and West, South and East Asia. Thalassemia is inherited, which means the condition is passed from a biological parent to their child.
Symptoms and Causes
What causes thalassemia?
Hemoglobin consists of four protein chains, two alpha globin chains and two beta globin chains. Each chain — both alpha and beta — contains genetic information, or genes, passed down from your parents. Think of these genes as the “code” or programming that controls each chain and (as a result) your hemoglobin. If any of these genes are defective or missing, you’ll have thalassemia.
- Alpha globin protein chains consist of four genes, two from each parent.
- Beta globin protein chains consist of two genes, one from each parent.
The thalassemia you have depends on whether your alpha or beta chain contains the genetic defect. The extent of the defect will determine how severe your condition is.
What are the types of thalassemia?
Thalassemia is classified as trait, minor, intermedia and major to describe how severe the condition is. These labels represent a range where having a thalassemia trait means that you may experience mild anemia symptoms or no symptoms at all. You may not need treatment. Thalassemia major is the most serious form and usually requires regular treatment.
There are two types of thalassemia — alpha thalassemia and beta thalassemia — named after defects in these chains.
You inherit four genes, two from each parent, that make alpha globin protein chains. When one or more genes are defective, you develop alpha thalassemia. The number of defective genes you inherit will determine whether you experience anemia symptoms and (if so) how severe they’ll be.
- One defective or missing alpha gene means that you won’t experience symptoms. Another name for this condition is alpha thalassemia minima.
- Two defective or missing alpha genes means that if you experience symptoms, they’ll likely be mild. Another name is alpha thalassemia minor.
- Three defective or missing alpha genes means that you’ll experience moderate to severe symptoms. Another name for this condition is Hemoglobin H disease.
- Four defective or missing alpha genes usually results in death. In those rare instances when a newborn survives, they’ll likely need lifelong blood transfusions. Another name for this condition is hydrops fetalis with Hemoglobin Barts.
You inherit two beta-globin genes, one from each parent. Your anemia symptoms and how severe your condition is depends on how many genes are defective and which part of the beta globin protein chain contains the defect.
- One defective or missing beta gene means that you’ll experience mild symptoms. Another name for this condition is beta thalassemia minor.
- Two defective or missing beta genes means that you’ll experience moderate to severe symptoms. The moderate version is called thalassemia intermedia. More severe beta thalassemia involving two gene mutations is called beta thalassemia major or Cooley’s anemia.
What are the symptoms of thalassemia?
Your experience will depend on the type of thalassemia you have and how severe it is.
Asymptomatic (no symptoms)
You likely won’t have symptoms if you’re missing one alpha gene. If you’re missing two alpha genes or one beta gene, you may be asymptomatic. Or, you may have mild anemia symptoms, like fatigue.
Mild to moderate symptoms
Beta thalassemia intermedia may cause mild anemia symptoms, or it may cause the following symptoms associated with more moderate disease:
- Growth problems.
- Delayed puberty.
- Bone abnormalities, such as osteoporosis.
- An enlarged spleen (the organ in your abdomen that plays a part in fighting infection).
You may eventually need surgery to correct skeletal problems. Your healthcare provider may need to remove your spleen if it grows too large.
Missing three alpha genes (Hemoglobin H disease) often causes anemia symptoms at birth and leads to severe lifelong anemia. Beta thalassemia major (Cooley’s anemia) often leads to severe anemia symptoms noticeable by age 2.
Symptoms of severe anemia include those associated with mild to moderate disease. Additional symptoms may include:
- Poor appetite.
- Pale or yellowish skin (jaundice).
- Urine that’s dark or tea-colored.
- Irregular bone structure in your face.
Diagnosis and Tests
How is thalassemia diagnosed?
Moderate and severe thalassemia are often diagnosed in childhood because symptoms usually appear within the first two years of your child’s life.
Your healthcare provider may order various blood tests to diagnose thalassemia:
- A complete blood count (CBC) that includes measures of hemoglobin and the quantity (and size) of red blood cells. People with thalassemia have fewer healthy red blood cells and less hemoglobin than normal. They may also have smaller-than-normal red blood cells.
- A reticulocyte count (a measure of young red blood cells) may indicate that your bone marrow isn’t producing enough red blood cells.
- Studies of iron will indicate whether the cause of your anemia is an iron deficiency or thalassemia.
- Hemoglobin electrophoresis is used to diagnose beta thalassemia.
- Genetic testing is used to diagnose alpha thalassemia.
Management and Treatment
How is thalassemia treated?
Standard treatments for thalassemia major are blood transfusions and iron chelation.
- A blood transfusion involves receiving injections of red blood cells through a vein to restore normal levels of healthy red blood cells and hemoglobin. You’ll receive transfusions every four months with moderate or severe thalassemia, and with beta thalassemia major, every two to four weeks. Occasional transfusions may be needed (for instance, during times of infection) for hemoglobin H disease or beta thalassemia intermedia.
- Iron chelation involves the removal of excess iron from your body. A danger with blood transfusions is that they can cause iron overload. Too much iron may damage organs. If you receive frequent transfusions, you’ll receive iron chelation therapy (which you can take as a pill).
- Folic acid supplements can help your body make healthy blood cells.
- Bone marrow and stem cell transplant from a compatible related donor is the only treatment to cure thalassemia. Compatibility means the donor has the same types of proteins, called human leukocyte antigens (HLA), on the surface of their cells as the person receiving the transplant. Your healthcare provider will inject bone marrow stem cells from your donor into your bloodstream during the procedure. The transplanted cells will start to make new, healthy blood cells within one month.
- Luspatercept is an injection that’s given every three weeks and can help your body make more red blood cells. It’s approved in the U.S. for the treatment of transfusion-dependent beta thalassemia.
What are the complications of thalassemia?
Your body may get too much iron (iron overload), either from frequent blood transfusions or the disease itself. Too much iron can cause damage to your heart, liver, and endocrine system. Your endocrine system includes glands that produce hormones that regulate processes throughout your body.
You may get frequent severe infections, especially if you receive a lot of blood transfusions. The infections may be carried in the blood you receive during a transfusion. Healthcare providers carefully screen donor blood during transfusions to prevent this from happening.
Can thalassemia be prevented?
You can’t prevent thalassemia, but genetic testing can reveal whether you or your partner carry the gene. Knowing this information can help you plan your pregnancy if you plan to conceive.
Speak to a genetic counselor for guidance on family planning if you suspect you or your partner may carry gene mutations for thalassemia.
Outlook / Prognosis
Can thalassemia be cured?
A bone marrow transplant from a compatible sibling offers the best chance at a cure for thalassemia. Unfortunately, most people with thalassemia lack a suitable sibling donor. Also, a bone marrow transplant is a high-risk procedure that may result in severe complications, including death.
Meet with a thalassemia specialist to determine whether you’re a candidate for a transplant. Choosing a high-volume hospital that regularly handles bone marrow transplants improves your chance of a cure while reducing your risk of complications.
What is the life expectancy of someone with thalassemia?
You should expect a normal life expectancy if you have mild thalassemia. Even if your condition is moderate or severe, you have a good chance of long-term survival if you follow your treatment program (transfusions and iron chelation therapy).
Heart disease from iron overload is the leading cause of death in people with thalassemia, so keeping up with your iron chelation therapy is extremely important.
What kind of ongoing care will I need?
You’ll need frequent complete blood counts and blood iron tests. Your healthcare provider may recommend yearly heart function and liver function tests. They may also recommend tests for viral infection (as having thalassemia increases your risk of certain serious infections). You also will need a yearly test for iron overload in your liver.
A note from Cleveland Clinic
Thalassemia is a treatable condition. Your symptoms, the types of treatments you’ll need and how often you’ll need them depend on how mild or severe your thalassemia is. Ask your healthcare provider how your condition will determine your need for ongoing care. If you’re planning to become pregnant and suspect you or your partner may carry genes for thalassemia, seek testing and advice from a genetic counselor.
Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy