Beta Thalassemia

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It is possible that the main title of the report Beta Thalassemia is not the name you expected.

Disorder Subdivisions

  • None

General Discussion

Beta thalassemia is an inherited blood disorder characterized by reduced levels of functional hemoglobin. Hemoglobin is found is red blood cells; it is the red, iron-rich, oxygen-carrying pigment of the blood. A main function of red blood cells is to deliver oxygen throughout the body. There are three main forms of beta thalassemia – minor, intermedia and major, which indicate the severity of the disease. Individuals with beta thalassemia minor usually do not have any symptoms (asymptomatic) and individuals often are unaware that they have the condition. Some individuals do experience a very mild anemia. Individuals with beta thalassemia major have a severe expression of the disorder; they often require regular blood transfusions and lifelong, ongoing medical care. The symptoms of beta thalassemia intermedia are widely variable and severity falls in the broad range between the two extremes of the major and minor forms. The characteristic finding of beta thalassemia is anemia, which is caused because red blood cells are abnormally small (microcytic), are not produced at the normal amounts, and do not contain enough functional hemoglobin. Consequently, affected individuals do not receive enough oxygen-rich blood (microcytic anemia) throughout the body. Affected individuals may experience classic signs of anemia including fatigue, weakness, shortness of breath, dizziness or headaches. Severe anemia can cause serious, even life-threatening complications if left untreated. Affected individuals are usually treated by regular blood transfusions. Individuals with beta thalassemia major and intermedia may develop excess levels of iron in the body (iron overload), which primarily results from repeated blood transfusions. Iron overload can potentially cause a variety of symptoms affecting multiple systems of the body, but can be treated by specific medications. Beta thalassemia is caused by mutations in the hemoglobin beta (HBB) gene. Individuals with beta thalassemia minor have a mutation in one HBB gene, while individuals with the intermediate and major forms have mutations in both HBB genes.

Thalassemia is a general term for a group of disorders in which there is reduced levels of hemoglobin, decreased red blood cell production and anemia. There are two main forms – alpha thalassemia and beta thalassemia, each with various subtypes. Beta thalassemia minor, also known as beta thalassemia trait, is a common condition. Beta thalassemia major was first described in the medical literature in 1925 by an American physician named Thomas Cooley. Beta thalassemia major is also known as Cooley's anemia. Today, the classic clinical picture of beta thalassemia major is primarily seen in countries with insufficient resources to provide affected individuals with proper treatment (e.g. regular transfusions and iron-lowering medications).

Supporting Organizations

Children's Cancer & Blood Foundation

333 East 38th Street, Suite 830
New York, NY 10016-2745
Tel: (212)297-4336
Fax: (212)297-4340

Cooley's Anemia Foundation, Inc.

330 7th Ave
Suite 900
New York, NY 10001
Tel: (212)279-8090
Fax: (212)279-5999
Tel: (800)522-7222

Genetic and Rare Diseases (GARD) Information Center

PO Box 8126
Gaithersburg, MD 20898-8126
Tel: (301)251-4925
Fax: (301)251-4911
Tel: (888)205-2311

March of Dimes

1275 Mamaroneck Avenue
White Plains, NY 10605
Tel: (914)997-4488
Fax: (914)997-4763
Email: or
Website: and

NIH/National Heart, Lung and Blood Institute

P.O. Box 30105
Bethesda, MD 20892-0105
Tel: (301)592-8573
Fax: (301)251-1223

Thalassemia Support Foundation

PO Box 26398
Santa Ana, CA 92799

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders (NORD). For a full-text version of this report, go to and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only.

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This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

Last Updated:  5/1/2015
Copyright  2015 National Organization for Rare Disorders, Inc.