Frequency of α-Globin Gene Triplications and Their Interaction with β-Thalassemia Mutations

Abstract

Our protocol for specialized diagnostics includes routine α-globin gene analysis for all blood samples referred to our diagnostic laboratory. α-Globin gene triplication is found to be present in more than 1% of samples tested. Since all cases with single α-gene triplications are associated with normal hematological parameters, we assume that preselection does not bias our observation and that α-globin gene triplications should be expected at the same frequency in the unselected Dutch multiethnic population as well. We have compared the average hematological parameters of β-thalassemia (β-thal) carriers with those of carriers with an associated α-gene triplication. In all cases, a single additional α gene had a very limited effect on the β-thal minor phenotypes.

Keywords:

• α−Triplications
• Hb A₂
• Frequency
• β−Thalassemia