ABSTRACT
alpha-Globin gene triplications may exacerbate the alpha chain and beta chain imbalance in beta-thalassemia (beta-thal) and may compensate for the effect of alpha-globin gene deletion in alpha-thal. Identification of an alpha-globin gene triplication is, therefore, valuable in predicting the clinical phenotype of the thalassemias. To be able to detect alpha-globin gene triplications, we have modified an existing multiplex polymerase chain reaction (PCR) assay for the seven most prevalent alpha-globin gene deletions by incorporating two triplication-specific primers and concurrently substituting one of the original primers by a newly designed primer. This modified multiplex PCR assay was evaluated by performing the assay on archival DNA samples and on peripheral blood samples from 163 suspected thalassemia cases. It was found to function properly. Our assay thereby represents the first multiplex PCR assay that can detect both the seven most prevalent alpha-globin gene deletions and the alphaalphaalpha(anti 3.7) alpha-globin gene triplication in a single-tube reaction.
