Largest-Ever Gene Study of Type 2 Diabetes Finds Variants across Many Ethnic Groups

he largest genetics study to date of type 2 diabetes (T2D) has identified new gene variants associated with risk for the common metabolic disease. An international scientific consortium, studying multiethnic populations, uncovered genes that may point to biological targets for developing more effective drugs for T2D.

Multiple genes and environmental factors interact with T2D, which affects nearly 300 million people worldwide. The majority of the gene variants remain undiscovered.

“Scientists have identified only about 10 percent of the genetic variants contributing to T2D, and most previous studies have been based on people of European ancestry,” said senior co-author Brendan J. Keating, Ph.D., of the Center for Applied Genomics at The Children’s Hospital of Philadelphia. This international study found that many gene variants associated with T2D overlap across multiple ethnic groups.” The current study included subjects with African-American, Hispanic, Asian and European ancestry.

The study appears online today in the American Journal of Human Genetics. The study’s other senior co-author was Richa Saxena, Ph.D., from Massachusetts General Hospital and Harvard Medical School.

The research consortium performed a meta-analysis of 39 existing studies of multiethnic populations, comprising over 17,000 cases of individuals with T2D, compared to 70,000 control subjects. This large-scale genetic screening used a customized gene analysis tool to examine 50,000 genetic variants across 2,100 genes known to be associated with cardiovascular and metabolic functions.

Diabetes and Ethnicity

Global studies on ethnic groups and minorities and the rising incidence of diabetes have revealed one factor in particular; ethnicity can increase or decrease one's risk of developing diabetes.

Whilst in some cases this can be explained by access to healthcare and other socio-economic factors, studies have proved that even with equal access prevalence of diabetes differs between people of different ethnicity.

Ethnicity facts

Type 2 diabetes is up to 6 times more likely in people of South Asian descent
Type 2 diabetes is up to three times more likely in African and Africa-Caribbean people
Furthermore, diabetes affects different ethnic groups in different ways.

The researchers identified variants in four previously unknown genes associated with T2D, discovered six new independent genetic signals in known T2D genes, and verified 16 previously reported T2D-linked variants. A total of nearly 40 gene variants have now been found to raise or lower the risk of T2D. Keating says the current study’s genome-wide screening approach in large multi-ethnic samples should be effective in discovering additional diabetes gene variants relevant to multiple ethnic populations.