New Genetic Risk Factor for Type 2 Diabetes Uncovered

Another genetic factor has now been found to contribute to an increased risk of developing type 2 diabetes, particularly the elevated risk among Mexican and other Latin American populations.

Upon performing a study in Mexican and Mexican American populations, an international team from Mexico and the USA—the SIGMA (Slim Initiative in Genomic Medicine for the Americas) Type 2 Diabetes Consortium—has discovered a risk-gene for type 2 diabetes that had gone undetected in previous efforts. Carriers of one copy of the higher risk allele are 25% (and carriers with two copies 50%) more likely to have diabetes. The higher risk allele was found in up to 50% of the population with recent Native American ancestry, including Latin Americans. It is found in about 20% of East Asians, and is rare in populations from Europe and Africa.

“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,” said José Florez, Broad Institute (Cambridge, MA, USA) associate member, associate professor of medicine at Harvard Medical School, and assistant physician at the Massachusetts General Hospital. The elevated frequency of this risk gene in Latin Americans could account for as much as 20% of the populations’ increased prevalence of type 2 diabetes.

A description of the discovery and initial characterization of the newly implicated gene—named SLC16A11—was published online December 25, 2013, in the journal Nature. About 9 million single-nucleotide-polymorphisms (SNPs) were analyzed in 8,214 Mexicans and other Latin Americans: 3,848 with type 2 diabetes and 4,366 nondiabetic controls. “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,” said Teresa Tusie-Luna, project leader at the Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán and principal investigator at the Biomedical Research Institute, National University of Mexico.

This is also the first time SLC16A11 has been highlighted as playing a role in human disease, and little information is available about its function. The paper reveals some initial clues about its possible connection to type 2 diabetes. “One of the most exciting aspects of this work is that we’ve uncovered a new clue about the biology of diabetes,” said David Altshuler, deputy director and chief academic officer at the Broad Institute and a Harvard Medical School professor at Massachusetts General Hospital.

This effort was the result of a partnership between members of many institutions in the USA and Mexico and was conducted as part of the Slim Initiative for Genomic Medicine for the Americas (SIGMA), funded by the Carlos Slim Foundation through the Carlos Slim Health Institute (Instituto Carlos Slim de la Salud; Mexico City, Mexico). “Our extraordinary partners, both in Mexico and the USA, have made it possible to make historic advances in the understanding of the basic causes of type 2 diabetes mellitus. We hope that through our contributions we will be able to improve the ways in which the disease is detected, prevented, and treated,” said Roberto Tapia-Conyer, CEO, Carlos Slim Foundation.

Related Links:
Broad Institute of Harvard and MIT
Carlos Slim Foundation, Health Institute
Massachusetts General Hospital