Thalassemias

Overview

What is thalassemia?

Red blood cells transport oxygen throughout the body; hemoglobin is the protein in red blood cells that actually carries the oxygen. Thalassemia (thal-uh-SEE-me-uh) is a group of disorders that affect the body's ability to produce normal hemoglobin.

People who have thalassemia produce fewer healthy hemoglobin proteins, and their bone marrow produces fewer healthy red blood cells.

Thalassemias can cause mild or severe anemia and other complications that can occur over time (such as iron overload). Symptoms of anemia include fatigue, difficulty breathing, dizziness, and a pale skin tone.

Who is at risk for thalassemia?

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 a parent to their child.

Symptoms and Causes

What are the types of thalassemia?

Four protein chains make up hemoglobin — 2 alpha globin and 2 beta globin chains. There are 2 major types of thalassemia – alpha thalassemia and beta thalassemia – named after defects that can occur in these protein chains.

Alpha Thalassemia

Four genes, 2 from each parent, are required to make alpha globin protein chains. When 1 or more genes are missing, it produces alpha thalassemia. This chart describes the different types of alpha thalassemia.

  • Missing alpha genes: 1
    • Disorder: silent carrier
    • Anemia symptoms: none
    • Other names: Alpha thalassemia - 2 trait, alpha thalassemia minima
  • Missing alpha genes: 2
    • Disorder: trait
    • Anemia symptoms: mild
    • Other names: Alpha thalassemia - 1 trait, alpha thalassemia minor
  • Missing alpha genes: 3
    • Disorder: Hemoglobin H
    • Anemia symptoms: moderate
    • Other names: Hemoglobin H disease
  • Missing alpha genes: 4
    • Disorder: major
    • Anemia symptoms: fatal
    • Other names: 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.

Beta Thalassemia

There are normally 2 beta globin genes, one from each parent. Beta thalassemia is a change in 1 or both of the beta globin genes. This chart describes the different types of beta thalassemia.

  • Affected beta genes:1
    • Disorder: silent carrier
    • Anemia symptoms: mild
    • Other names: Beta thalassemia minor
  • Affected beta genes: 1
    • Disorder: trait
    • Anemia symptoms: mild
  • Affected beta genes: 2
    • Disorder: intermedia
    • Anemia symptoms: moderate
  • Affected beta genes: 2
    • Disorder: major
    • Anemia symptoms: severe
    • Other names: 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 with thalassemia can get too much iron in their bodies (iron overload), either from frequent blood transfusions or from the disease itself. Too much iron can cause damage to your heart, liver, and endocrine system, which includes glands that produce hormones that regulate processes throughout your body.

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.

Diagnosis and Tests

How are thalassemias diagnosed?

Moderate and severe thalassemias are often diagnosed in childhood because symptoms usually appear during the first 2 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).
  • Hemoglobin electrophoresis is used to diagnose beta thalassemia.
  • Genetic testing is used to make a diagnosis of alpha thalassemia.

Management and Treatment

How is thalassemia treated?

Standard treatments for patients with thalassemia major are blood transfusions and iron chelation.

  • 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 causedamage to other organs. Because of this, patients who receive frequent transfusions also require iron chelation therapy, which can be given in pill form.
  • Nutritional supplements, in the form of folic acid supplements, and monitoring of B12 levels are important, as these nutrients are key components to making healthy blood cells.
  • Bone marrow and stem cell transplant from a compatible related donor is the only treatment that can cure thalassemia. It 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 1 month, the transplanted bone marrow stem cells will start to make new, healthy blood cells. Given the high risks of a bone marrow transplant, it is not routinely recommended for those with mil or moderate thalassemia.

Prevention

Can thalassemia be prevented?

Currently, thalassemia cannot be prevented because it is an inherited (passed down from parents to the child) blood disorder. It is possible to identify carriers of this disorder with genetic testing.

Outlook / Prognosis

What is the prognosis (outlook) for patients with thalassemias?

Patients with mild thalassemia can expect a normal life expectancy. Patients with moderate or severe thalassemias have a good chance of long-term 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. Patients with thalassemia may need surgery to correct skeletal problems.

Living With

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.

Last reviewed by a Cleveland Clinic medical professional on 07/14/2018.

References

  • National Heart, Lung, and Blood Institute. What Are Thalassemias? Accessed 3/5/2020.
  • Centers for Disease Control and Prevention. Thalassemia Accessed 3/5/2020.
  • American Academy of Family Physicians/FamilyDoctor.org. Thalassemia Accessed 3/5/2020.

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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

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