Thalassemia is an inherited blood disorder that affects your body’s ability to produce hemoglobin and healthy red blood cells. Types include alpha and beta thalassemia. Thalassemia may cause you to experience anemia-like symptoms that range from mild to severe. Treatment can consist of blood transfusions and iron chelation therapy.
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.
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Thalassemia can cause mild or severe anemia and other complications over time (such as iron overload). Symptoms of anemia include:
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.
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.
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.
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.
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.
Your experience will depend on the type of thalassemia you have and how severe it is.
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.
Beta thalassemia intermedia may cause mild anemia symptoms, or it may cause the following symptoms associated with more moderate disease:
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:
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:
Standard treatments for thalassemia major are blood transfusions and iron chelation.
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.
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.
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.
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.
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.
Last reviewed by a Cleveland Clinic medical professional on 06/03/2022.
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