An international consortium of researchers, including scientists at the Harvard-MIT Broad Institute, has identified three genes that contain genetic risk factors for type 2 diabetes.

The discovery represents an important leap in understanding common diseases, including strokes, heart attacks, and diabetes, from a genetics perspective, according to David M. Altshuler, one of the primary researchers involved with the discovery.

“The most important story here is that, it’s been clear for almost a century that common diseases such as diabetes run in families, and half of the risk is genetic susceptibility. But up until this year, no progress has been made towards understanding genetic bases of these common diseases,” said Altshuler, director of the Broad Institute’s Program in Medical and Population Genetics.

The findings are significant not only for their medical importance, but also because of the international, private-public partnership among several research groups.

The Diabetes Genetics Initiative, a collaboration founded in 2004 among experts from the Broad Institute, Novartis Institutes for BioMedical Research, and Lund University in Sweden, shared their findings with two others groups, one based in the U.K. and one in Finland.

Together, the three groups of scientists published their results in last Thursday’s online edition of Science. They also agreed to collaborate further in attempting to discover genes that are not currently thought of as risk factors for type 2 diabetes and in determining how the genes contribute to the disease.

“The amazing part of this collaboration is the fact that the three groups cross-validated their findings, allowing the full value of all three of the studies to emerge,” said Thomas E. Hughes, head of diabetes and metabolism research at Novartis.

Oxford University’s Mark McCarthy, a leading investigator of the U.K.-group, also praised the joint effort, calling it “unprecedented and definitely productive.”

“It’s been a great collaboration from the scientific and intellectual point of view, and we can achieve much more together than we can separately,” he said.

“What’s been learned here is that there are genes in places of the human genome that are completely mysterious,” Altshuler said.

Adopting recently developed technology from the Human Genome Project and the HapMap Project to find genes associated with human diseases from a raw sequence of the genome, the researchers used DNA chips to measure genetic variation.

Through testing millions of genes that may be related to type 2 diabetes, they found these three new genes that seem to be associated with decreasing the production of insulin in the pancreas, which is a risk factor of the disease.

“The fact that there are surprises is validation of how crucial this approach is,” Altshuler said.