Molecular basis of β-thalassemia in Karnataka, India.

In β-thalassemia, point mutations in the β-globin gene are largely responsible for either decreased or no β-globin synthesis. The β-globin gene has three exons and two introns. The molecular characterization of β-thalassemia is absolutely necessary for carrier screening, for genetic counseling, and to offer prenatal diagnosis. The objective of the present study was to identify the rare mutations in β-globin gene of β-thalassemia patients. We have sequenced the entire β-globin gene in 36 clinically identified thalassemia patients from the Karnataka region using polymerase chain reaction and sequencing. Our analysis revealed 11 β-thalassemia variants. The most common being IVSII-16 G>C, IVSI-5G>C, IVSII-74 T>G, codon 3 (T>C), and Poly A site (T>C). In addition, we have also documented a novel deletion at codon 6 (-CT) (HBB:c.16delCT). These data are useful in future molecular screening of the population for implementing a thalassemia prevention and control program. Further it is found that family studies and comprehensive hematological analyses would provide useful insights for accurate molecular diagnosis of thalassemia phenotype and offers an interesting subject for further investigations in the Indian populations.