Beta thalassemia patients demonstrate an inherited defect in beta globin chain production. Since two gene loci are coding for beta chain production on chromosome 11, different forms of beta thalassemia depend on whether one or both loci have been fully or partially affected. The greater the number of loci deleted or inactivated, the greater the severity of the anemia that develops.
Many different mutations result from partial deletions of beta genes. This unit of study deals only with forms of beta thalassemia that have entire loci deleted. In addition, deletions of other globin genes coded for on chromosome 11 can result in combinations as delta-beta thalassemia.
Certain regions of the world have more severe forms of beta thalassemia. These include northern Italy, Algeria, Greece, Saudi Arabia, and Southeast Asia. Individuals of African descent have a higher frequency of milder forms of beta thalassemia than individuals in other regions.
