Beta thalassemia demonstrates problems with beta globin chain production. One or two loci that code for the beta chain may be deleted from chromosome 11. The greater the number of loci deleted or inactivated, the greater the severity of the anemia which develops.

Many different mutations exist that result from partial deletions of beta genes. This unit of study deals only with the forms of beta thalassemia that have entire loci deleted.

Deletions of additional globin genes coded for on chromosome 11 can result in such combinations as delta-beta thalassemia.