Four newly identified genes predispose people to developing Type 2 diabetes, international researchers say.

British, American and Finnish researchers collaborated on the research, which appears in Friday's issue of the journal Science.

"This research helps us to understand that, for most people at least, an individual's risk of developing diabetes as they get older is influenced by a number of genes, as well as by their environment," said Prof. Mark McCarthy of the University of Oxford, one of the lead authors.

The findings also confirm the existence of six other genes thought to be involved in Type 2 diabetes, raising the total known genes linked to the disease to 10.

The newly identified genes, called IGF2BP2, CDKAL1, and CDKN2A and CDKN2B, all come in two versions, one of which is linked to an increased risk of developing the disease.

Each high-risk version increased the risk of Type 2 diabetes by between 10 to 20 per cent, said the researchers.

They stressed that predictions of disease risk need to be interpreted with caution since the sample included people with affected siblings and healthy controls that excluded anyone with impaired glucose tolerance or fasting glucose.

Type 2 diabetes occurs when the pancreas either does not make enough insulin, or makes it but cannot use it properly. It is usually controlled through diet.

The role of the genes is unclear, although two seem to be involved in the development, function and regeneration of insulin-producing beta cells in the pancreas.

McCarthy and his colleagues looked for the genes in 2,000 people with Type 2 diabetes and 3,000 controls, and then confirmed the findings from another 9,000 samples from the U.K.

Researchers also scanned the genomes of more than 2,300 Finnish people, about half of whom had Type 2 diabetes. Those findings were validated with scans from 3,000 Swedish and Finnish participants as well as the initial 5,000 British participants.

"While more work remains to be done, the newly identified genetic variants may point us in the direction of valuable new drug targets for the prevention or treatment of Type 2 diabetes," said Dr. Griffin Rodgers of the U.S. National Institute of Diabetes and Digestive and Kidney Diseases, one of the funders for the U.S.-Finnish team.

Type 2 diabetes affects about 1.3 million Canadians, and the number is expected to reach three million by 2010.