The IVS-II-837 (T>G) Appears to be a Relatively Common 'Rare' β-Globin Gene Mutation in β-Thalassemia Patients in Karnataka State, South India

Abstract

β-Thalassemia (β-thal) is a common single gene autosomal recessive disorder resulting in severe anemia due to reduced or absent β-globin polypeptide synthesis. The disease is caused by mutations in the β-globin gene; eight common mutations are proposed to cause the majority of β-thal in India. However, the occurrence of a region-specific mutation spectrum in India has also been suggested. We had earlier carried out analyses of the β-globin gene mutation spectrum from southern Indian states of Andhra Pradesh and Karnataka. In the current study, we have analyzed three of 73 transfusion-dependent patients visiting a referral hospital in Karnataka State, South India, who did not carry any of the 22 common β-globin gene mutations as determined by reverse dot-blot analysis. The IVS-II-837 (T>G) (β⁺) (HBB:c.316-14TG) mutation was detected in two of the three patients analyzed suggesting a higher occurrence of the mutation in β-thal patients in Karnataka when compared to other regions of India. The rare polyadenylation (poly A) site (T>C) (AATAAA>AACAAA; β⁺) mutation was detected in the third patient. The IVS-II-837 mutation was also identified in asymptomatic carrier parents during routine high performance liquid chromatography (HPLC)-based Hb A_1c screening in suspected diabetes patients. This is the first report of the identification of β-thal trait through HPLC-based diabetes screening in India, revealing the importance of linking diabetes screening with screening for thalassemia.

• β-Thalassemia (β-thal)
• β-Globin
• Mutation

ACKNOWLEDGMENTS

We gratefully acknowledge all patients who kindly consented to be a part of this study. A core grant from the Department of Biotechnology, Government of India to MDB’s host institution is gratefully acknowledged.

Declaration of Interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.