What is Beta Thalassemia?

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Beta thalassemia is an inherited blood disorder caused by gene mutations in which the body makes too little hemoglobin—the protein in red blood cells that carries oxygen throughout the body. In this condition red blood cells are destroyed as well. Over time insufficient hemoglobin can lead to anemia (a low red blood cell count, or RBC) and other complications. People with the most severe form of the disorder, beta thalassemia major, or Cooley's anemia, typically are treated with regular blood transfusions; those with the lesser type, beta thalassemia intermedia, may need transfusions less frequently.

Red blood cells in vein
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There are three types of beta thalassemia.

  • Beta thalassemia trait, in which a person carries the gene for the disorder but does not have symptoms. It sometimes is called thalassemia minor.
  • Beta thalassemia intermedia, a relatively mild form of the disorder
  • Beta thalassemia major, or Cooley’s anemia, which is the most severe form

Beta thalassemia is most prevalent among people of Mediterranean, Asian, Indian, and African descent.


The symptoms of beta thalassemia depend on the type and severity of the disorder. People with beta thalassemia minor may have very mild anemia but usually don't develop discernible symptoms. Some may never even know they're carrying the altered gene.

Although the two mutated HBB genes are present at birth, babies born with either beta thalassemia intermedia or Cooley's anemia may not have symptoms until between 3 and 6 months; some children with beta thalassemia do not develop symptoms until age 2.

Regardless of when a child with beta thalassemia becomes symptomatic, they are likely to experience the following:

  • Anemia
  • Fatigue
  • Weakness
  • Shortness of breath
  • Yellowish or pale skin
  • Slow growth
  • Dark urine
  • Poor appetite
  • Fussiness

For those with Cooley's anemia, symptoms can progress and complications may develop, such as:

  • Abdominal swelling
  • Bone deformities or broken bones due to changes in the bone marrow where red blood cells are produced
  • Splenomegaly, a condition in which the spleen, which filters red blood cells, is overworked and becomes enlarged
  • Infections


Although most of the time thalassemia major will be identified on the newborn screen, people with thalassemia intermedia may not be identified until years later. These people are generally identified on routine complete blood count (CBC). The CBC will reveal a mild to moderate anemia with very small red blood cells. This can be confused with iron deficiency anemia.

Diagnosis is confirmed by a hemoglobin profile (also called electrophoresis). In beta thalassemia intermedia and trait this testing reveals elevation in hemoglobin A2 (a second form of adult hemoglobin) and sometimes F (fetal). Alpha thalassemia intermedia is generally called hemoglobin H disease as this is the predominant hemoglobin seen on the profile.

Beta thalassemia can be diagnosed through various blood tests. Moderate and severe beta thalassemia are usually diagnosed in early childhood or by the time your are 2 years old because signs and symptoms such as anemia usually present very early. If your parents have the disorder, you may have been tested and diagnosed at birth or as a toddler, especially if you exhibited anemia at a very young age.

The various tests used to diagnose beta thalassemia include:

  • The newborn screen, which is testing administered routinely to most infants at birth to identify any inherited conditions. This can detect beta thalassemia or, at least, red-flag characteristics of the disorder in the blood for further monitoring by a hematologist. The newborn screen involves taking a small sample of blood and sending it to a lab for evaluation.
  • A complete blood count (CBC), which measures hemoglobin and the quantity and size of red blood cells. The CBC will also reveal a mild to moderate anemia with very small red blood cells, which are typical of beta thalassemia. (Sometimes, however, a diagnosis can be confused with iron deficiency anemia)

People who have milder forms of thalassemia might be diagnosed after a routine blood test shows they have anemia. Doctors may also suspect and test for beta thalassemia in people of African, Mediterranean, or Eastern Asian descent who seem to have anemia.

  • A reticulocyte count, which determines the health of bone marrow and is often part of a workup when testing for anemia, may indicate that bone marrow is not producing an adequate number of red blood cells.
  • Check of iron levels in the blood will show whether the cause of the anemia is iron deficiency or thalassemia.

Since beta thalassemia is a genetic disorder passed from parent to child, several other tests that can help predict the presence of the gene, and possible severity of beta thalassemia:

  • Hemoglobin electrophoresis, which is a blood test for parents designed to detect various genetic abnormalities in hemoglobin structure, can show the levels of hemoglobin.
  • Prenatal testing can reveal the severity of beta thalassemia in cases where parents carry the gene. These may include: chorionic villus sampling done around the 11th week of pregnancy removing a tiny piece of the placenta for evaluation; and amniocentesis, which is done around the 16th week of pregnancy and involves examining a sample of the fluid that surrounds the fetus.


The standard treatments for people with moderate or severe beta thalassemia are blood transfusions, iron chelation therapy, and folic acid supplements:

  • Blood transfusions: A transfusion of red blood cells can compensate for the shortage and ensures normal hemoglobin levels. People with beta thalassemia major often need transfusions every two or four weeks throughout their lives; those with beta thalassemia intermedia may require only occasional transfusions, during periods of illness or puberty.
  • Iron chelation therapy: This helps the body remove excess, and potentially harmful, amounts of iron from the blood—which can result from many transfusions. Iron chelation is administered orally or through an infusion under the skin.
  • Splenectomy: Use of this procedure has declined in recent years, but removal of the spleen is sometimes considered when chelation therapy isn't working.
  • Folic acid supplements: Folic acid is a B vitamin that helps build healthy red blood cells. Your doctor may recommend folic acid supplements in addition to blood transfusions and iron chelation therapy.
  • Bone marrow and stem cell transplant: A blood and marrow stem cell transplant replaces faulty stem cells with healthy ones from another person (a donor). Stem cells are the cells inside bone marrow that make red blood cells. Although this could be a possible cure for beta thalassemia, only a small number of people who have severe thalassemia can find a good donor match for this risky procedure.

People who are beta thalassemia carriers or who have been identified with the trait but have mild symptoms or none at all, usually require very little by way of treatment.

A Word From Verywell

If you or members of your family have beta thalassemia or the gene for beta thalassemia, it is a good idea to talk to your doctor if you are thinking about having children. A genetic counselor can help determine the risk of passing the disorder on to your offspring. If you're expecting a baby and you and your partner are thalassemia carriers, you may want to consider prenatal testing. While these tests admittedly seem scary and foreboding, they will actually assuage your anxiety and help you be prepared, whatever the outcome.

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