Molecular Basis of α-Thalassemia in Iran

Alpha-thalassemia (α-thal) is probably the most prevalent monogenic condition in the world. Deletions are the most common types of mutations in α-thal, followed by point mutations and small insertion/deletion. In the context of national screening program for prevention of thalassemia and hemoglobinopathies in Iran, α-thal carriers have come to more attention. Therefore, the frequency and distribution of α-globin mutations in various regions of the country have been studied in recent years. A comprehensive search was performed in PubMed, Scopus, and national databases for finding reports on mutation detection in α-thal carriers and HbH disease with Iranian origin. The mutation data of 10849 α-thal carriers showed that -α(3.7) and α(-5NT) were the most common deletional and nondeletional mutations, respectively. In HbH disease cases, the -α(3.7)/--(MED) was the most prevalent genotype. Overall, 42 different mutations have been identified in α-globin cluster reflecting the high heterogeneity of the mutations in Iranian populations.