Thalassemia

Definition

Thalassemia is a blood disorder passed down through families (inherited) in which the body makes an abnormal form of hemoglobin, the protein in red blood cells that carries oxygen. The disorder results in excessive destruction of red blood cells, which leads to anemia.

See also:

• Hemolytic anemia
• Sickle cell disease

Alternative Names

Mediterranean anemia; Cooley's anemia; Beta thalassemia; Alpha thalassemia

Causes, incidence, and risk factors

Hemoglobin is made of two proteins: Alpha globin and beta globin. Thalassemia occurs when there is a defect in a gene that helps control production of one of these proteins.

There are two main types of thalassemia:

• Alpha thalassemia occurs when a gene or genes related to the alpha globin protein are missing or changed (mutated).
• Beta thalassemia occurs when similar gene defects affect production of the beta globin protein.

Alpha thalassemias occur most commonly in persons from southeast Asia, the Middle East, China, and in those of African descent.

Beta thalassemias occur in persons of Mediterranean origin, and to a lesser extent, Chinese, other Asians, and African Americans.

There are many forms of thalassemia. Each type has many different subtypes. Both alpha and beta thalassemia include the following two forms:

• Thalassemia major
• Thalassemia minor

You must inherit the defective gene from both parents to develop thalassemia major.

Thalassemia minor occurs if you receive the defective gene from only one parent. Persons with this form of the disorder are carriers of the disease and usually do not have symptoms.

Beta thalassemia major is also called Cooley's anemia.

Risk factors for thalassemia include:

• Asian, Chinese, Mediterranean, or African American ethnicity
• Family history of the disorder

Symptoms

The most severe form of alpha thalassemia major causes stillbirth (death of the unborn baby during birth or the late stages of pregnancy).

Children born with thalessemia major (Cooley's anemia) are normal at birth, but develop severe anemia during the first year of life.

Other symptoms can include:

• Bone deformities in the face
• Fatigue
• Growth failure
• Shortness of breath
• Yellow skin (jaundice)

Persons with the minor form of alpha and beta thalassemia have small red blood cells (which are identified by looking at their red blood cells under a microscope), but no symptoms.

Signs and tests

A physical exam may reveal a swollen (enlarged) spleen.

A blood sample will be taken and sent to a laboratory for examination.

• Red blood cells will appear small and abnormally shaped when looked at under a microscope.
• A complete blood count (CBC) reveals anemia.
• A test called hemoglobin electrophoresis shows the presence of an abnormal form of hemoglobin.

A test called mutational analysis can help detect alpha thalassemia that cannot be seen with hemoglobin electrophoresis.

Treatment

Treatment for thalassemia major often involves regular blood transfusions and folate supplements.

If you receive blood transfusions, you should not take iron supplements. Doing so can cause a high amount of iron to build up in the body, which can be harmful.

Persons who receive significant numbers of blood transfusions need a treatment called chelation therapy to remove excess iron from the body.

A bone marrow transplant may help treat the disease in some patients, especially children.

Support Groups

Expectations (prognosis)

Severe thalassemia can cause early death due to heart failure, usually between ages 20 and 30. Getting regular blood transfusions and therapy to remove iron from the body helps improve the outcome.

Less severe forms of thalassemia usually do not shorten lifespan.

Genetic counseling and prenatal screening may help people with a family history of this condition who are planning to have children.

Complications

Untreated, thalassemia major leads to heart failure and liver problems, and makes a person more likely to develop infections.

Blood transfusions can help control some symptoms. However, they may result in too much iron, which can damage the heart, liver, and endocrine system.

Calling your health care provider

Call for an appointment with your health care provider if:

• You or your child has symptoms of thalassemia
• You are being treated for the disorder and new symptoms develop

Prevention

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References

Giardina PJ, Forget BG. Thalassemia syndromes. In: Hoffman R, Benz EJ, Shattil SS, et al., eds. Hematology: Basic Principles and Practice. 5th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2008:chap 41.

DeBaun MR, Frei-Jones M, Vichinsky E. Hemoglobinopathies. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 456.