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Beta thalassemia is a blood disorder that reduces the production of hemoglobin. Hemoglobin is the iron-containing protein in red blood cells that carries oxygen to cells throughout the body. In people with beta thalassemia, low levels of hemoglobin lead to a lack of oxygen in many parts of the body. Affected individuals present with anemia, pale skin, weakness, fatigue, and more serious complications. People with beta thalassemia are at an increased risk of developing abnormal blood clots. Thalassemia has been classified into two types: major and intermedia.

Mutations in the HBB gene cause beta thalassemia. The HBB gene provides instructions for making a protein called beta-globin. Beta-globin is a component of hemoglobin. Hemoglobin consists of four protein subunits, typically two subunits of beta-globin and two subunits of another protein called alpha-globin. Some mutations in the HBB gene prevent the production of any beta-globin. The absence of beta-globin is referred to as beta-zero (B0) thalassemia. Other HBB gene mutations allow some beta-globin to be produced but in reduced amounts. A reduced amount of beta-globin is called beta-plus (B+) thalassemia. Having either B0 or B+ thalassemia does not necessarily predict disease severity, however; people with both types have been diagnosed with thalassemia major and thalassemia intermedia.

Thalassemia major and thalassemia intermedia are inherited in an autosomal recessive pattern, which means both copies of the HBB gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. Sometimes, however, people with only one HBB gene mutation in each cell develop mild anemia. These mildly affected people are said to have thalassemia minor.

Type OMIM Gene Description
Thalassemia major, also known as Cooley's anemia 613985 HBB Symptoms appear within the first 2 years of life. Life-threatening anemia, failure to thrive, yellowing of the skin and whites of the eyes, enlarged spleen, liver, and heart, and bones may be misshapen. Some adolescents with thalassemia may experience delayed puberty. Many people with thalassemia major have such severe symptoms that they need frequent blood transfusions to replenish their red blood cell supply. Over time, an influx of iron-containing hemoglobin from chronic blood transfusions can lead to a buildup of iron in the body, resulting in liver, heart, and hormone problems.

Thalassemia intermedia

613985 HBB Milder form, signs and symptoms of thalassemia intermedia appear in early childhood or later in life. Affected individuals have mild to moderate anemia and may also have slow growth and bone abnormalities.

Methodology: Sequencing of entire coding region

Purpose: Confirmation of Clinical Diagnosis

ICD-10 Code D56.1

Test Requisition: Sequencing Requisition

CPT Codes: 81364 Cost: $530.00

Turn-around-time: 3-4 weeks

Specimen Requirements

Shipping Information


1. Olivieri NF. The beta-thalassemias. N Engl J Med. 1999 Jul 8;341(2):99-109. Review. Erratum in: N Engl J Med 1999 Oct 28;341(18):1407.

2. Panigrahi I, Agarwal S. Thromboembolic complications in beta-thalassemia: Beyond the horizon. Thromb Res. 2007;120(6):783-9. Epub 2007 Mar 7. Review.

3. Rund D, Rachmilewitz E. Beta-thalassemia. N Engl J Med. 2005 Sep 15;353(11):1135-46. Review.

4. Taher A, Isma'eel H, Cappellini MD. Thalassemia intermedia: revisited. Blood Cells Mol Dis. 2006 Jul-Aug;37(1):12-20. Epub 2006 Jun 5. Review.

5. Thein SL. Genetic insights into the clinical diversity of beta thalassaemia. Br J Haematol. 2004 Feb;124(3):264-74. Review.



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