GENETIC HETEROGENEITY OF BETA GLOBIN MUTATIONS AMONG ASIAN-INDIANS AND IMPORTANCE IN GENETIC COUNSELLING AND DIAGNOSIS

Abstract

There are an estimated 45 million carriers of β-thalassemia trait and about 12,000-15,000 infants with β-thalassemia major are born every year in India. The consanguinity rates are higher in India, and thalassemia major constitutes a significant burden on the health care system. In present study, β-thalassemia mutations were characterized in 300 thalassemia cases from 2007 to 2010 using ARMS-PCR and DNA sequencing. The five most common mutations accounted 79.3% of the studied chromosomes that includes IVS1-5(G>C), Cod 41-42(-TCTT), Cod8-9(+G), Cod16(-C) and 619bp del. Though IVS1-5(G>C) is most common mutation when all the communities were included, the percentage prevalence were calculated on sub caste basis and found that IVS1-5(G>C) percentage prevalence varied from 25 to 60 in Aroras & Khatris and Thakur respectively. Interestingly Cod41-42(-TCTT) mutation which is the second commonest among the mutations reported was totally absent in Kayasthas and Muslim community. These findings have implications for providing molecular diagnosis, genetic counseling and prenatal diagnosis to high risk couples of β-thalassemia.