New genetic risk factor for type 2 diabetes revealed

PUBLIC RELEASE DATE:

25-Dec-2013

Contact: Nicole Davis ndavis@broadinstitute.org 617-714-7152 Broad Institute of MIT and Harvard

Cambridge and Boston, MA; Los Angeles, CA; Mexico City, Mexico. Wed. December 25, 2013 An international team of researchers in Mexico and the United States has uncovered a new genetic clue that contributes to an increased risk of developing type 2 diabetes, particularly the elevated risk among Mexican and other Latin American populations.

The team, known as the SIGMA (Slim Initiative in Genomic Medicine for the Americas) Type 2 Diabetes Consortium, performed the largest genetic study to date in Mexican and Mexican American populations, discovering a risk gene for type 2 diabetes that had gone undetected in previous efforts. People who carry the higher risk version of the gene are 25 percent more likely to have diabetes than those who do not, and people who inherited copies from both parents are 50 percent more likely to have diabetes. The higher risk form of the gene has been found in up to half of people who have recent Native American ancestry, including Latin Americans. The variant is found in about 20 percent of East Asians and is rare in populations from Europe and Africa.

The elevated frequency of this risk gene in Latin Americans could account for as much as 20 percent of the populations' increased prevalence of type 2 diabetes the origins of which are not well understood.

"To date, genetic studies have largely used samples from people of European or Asian ancestry, which makes it possible to miss culprit genes that are altered at different frequencies in other populations," said co-corresponding author Jos Florez, a Broad associate member, an associate professor of medicine at Harvard Medical School and an Assistant Physician in the Diabetes Unit and the Center for Human Genetic Research at the Massachusetts General Hospital. "By expanding our search to include samples from Mexico and Latin America, we've found one of the strongest genetic risk factors discovered to date, which could illuminate new pathways to target with drugs and a deeper understanding of the disease."

A description of the discovery of the newly implicated gene named SLC16A11 and the consortium's efforts to characterize it, appear online in Nature December 25.

"We conducted the largest and most comprehensive genomic study of type 2 diabetes in Mexican populations to date. In addition to validating the relevance to Mexico of already known genetic risk factors, we discovered a major new risk factor that is much more common in Latin American populations than in other populations around the world. We are already using this information to design new studies that aim to understand how this variant influences metabolism and disease, with the hope of eventually developing improved risk assessment and possibly therapy," said Teresa Tusie-Luna, project leader at the Instituto Nacional de Ciencias Mdicas y Nutricin Salvador Zubirn and principal investigator at the Biomedical Research Institute, National University of Mexico.

This work was conducted as part of the Slim Initiative for Genomic Medicine for the Americas (SIGMA), a joint U.S.-Mexico project funded by the Carlos Slim Foundation through the Carlos Slim Health Institute. SIGMA focuses on several key diseases with particular relevance to public health in Mexico and Latin America, including type 2 diabetes and cancer. The current paper is the team's first report on type 2 diabetes.