CHENNAI: Scientists have found six new genes that trigger diabetes mellitus in South Asians. These genes are responsible for the early onset of diabetes in South Asians, including Indians. Scientists from the UK collaborated with doctors in India, Singapore, Pakistan, Mauritius and Sri Lanka on the study.
This is the first time studies have been conducted in South Asia, where more than 55 million people have diabetes, a majority of them from India and China. So far, scientists have discovered 42 genes associated with diabetes but all these studies were done on Europeans.
Although unhealthy diet, obesity and physical inactivity put people to risk of diabetes, doctors say South Asians have genes that make them susceptible to the disorder. “There is no other reason why South Asians should get diabetes in their 40s when Europeans get it in only in their mid or late 50s,” said Chennai-based diabetologist Dr V Mohan, who was part of the study.
Scientists collaborated across continents for the genetic-wide association study (GWAS) in South Asians, the findings of which were published in the medical journal, ‘Nature Genetics’, on Sunday. UKbased scientists Dr John C Chambers and Jaspal S Konnor from Imperial College London collaborated with 42 others for the research. “Our study might lead to treatments to prevent diabetes,” hopes Chambers.
From India, two ethnic groups were chosen – people from Punjab, Haryana, Himachal Pradesh, Delhi and Jammu Kashmir for a Sikh diabetes study, and south Indians for a Chennai Urban Rural Epidemiological study. A total of 58,587 South Asians took part, of which 20,119 had diabetes and 38,568 were healthy. The genomes of the participants were analysed to look for locations where variations were more common in those with diabetes. The scientists found the presence of six genes that were abnormally high in diabetics. Scientists concluded that these six genes – GRB14, ST6GAL1, VPS26A, HMG20A, AP3S2 and HNF4A – were associated with diabetes. While it is known that one of the genes — HNF4A alias Mody-1 gene – was common among children with diabetes in the West and some diabetics in India, the characteristics of the other genes are still a mystery. There are two approaches to genetic research. Until 2006, doctors used the hypothesisfree approach where they would identify a gene and then verify whether it caused a disease or disorder.. From 2006, scientists started the GWAS approach, where technology has made it possible to link multiple genes to a single disease.
New-Delhi-based Dr Dwaipayan Bharadwaj of Institute of Genomics and Integrative Biology said this approach helps unravel complex gene relationships. “These studies don’t take into account environmental factors but reveal gene associations,” he said. Dr Bharadwaj is working on a GWAS study exclusively for Indians.