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Thalassemia Types |
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There are two main types of thalassemia - "alpha" and "beta." The names refer to the part of the hemoglobin molecule that is missing or mutated.
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Alpha thalassemia is caused by a defect in or absence of two or more of the four "alpha" chains of the hemoglobin molecule. The alpha chains are located on chromosome 16. This type of thalassemia is divided into four categories:
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Beta thalassemia is caused by a mutation on one or both of the two genes on the "beta" chain of the hemoglobin molecule. The beta chain is found on chromosome 11. Unlike alpha thalassemia, beta genes are usually not missing, but are mutated. The hundreds of possible mutations make beta thalassemia more diverse than alpha thalassemia. There are three main types of beta thalassemia.
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