SNPWatch: Genetic Variants Associated with Type 2 Diabetes in South Asians and Europeans

Type 2 diabetes is characterized by very high levels of sugar in the blood and is the most common form of diabetes. Although eating rich food and leading a sedentary lifestyle contribute to the development of this disease, genetics also play a role.

For reasons unclear to researchers, South Asians are four times more likely to develop type 2 diabetes compared to Europeans. Up until last month–when a large genome-wide association study (GWAS) on type 2 diabetes in South Asians was published in Nature Genetics–very little was known about the genetic factors underlying these differences.

Type 2 Diabetes Among People of South Asian Ancestry

The authors behind this study carried out one of the largest type 2 diabetes studies to date, scanning the genomes of nearly 19,000 people with the disease and 40,000 without it, all of South Asian descent.

Their analysis identified six SNPs linked to this condition. When they combined their results with previously published findings in other ethnicities, they found suggestive evidence that five of the six SNPs associated with type 2 diabetes in Europeans. Similarly, there was some evidence that the majority of the genetic risk factors in Europeans were also linked to disease in South Asians. Only three genetic factors were not shared at all between the two groups.

Differences Between Men and Women

By performing a sex-specific analysis of the South Asian and European dataset, the researchers found that one SNP– near the UBBP4 gene–was linked to type 2 diabetes in women but not in men. Their data further indicated that the SNP was only associated with disease in women of European descent. The authors also looked to see if the six newly identified SNPs correlated with risk factors for diabetes. Some of those factors include such things as being overweight, but the researchers found no connection.

This study is the first of its kind to identify novel genetic factors for type 2 diabetes in South Asians, a population underrepresented in genetic studies. that is relatively understudied. The authors’ findings suggest that many genetic risk factors for type 2 diabetes are shared between Europeans and South Asians. At the same time, most of the shared factors had stronger statistical evidence of a connection in one ethnicity than the other.

More research is needed to elucidate the biology related to these differences. Read more about this study in in Nature Genetics.