Scientists have found six new genes linked to type 2 diabetes, a discovery that will improve understanding of how the disease develops.

Each of the disease variants of the genes raises the risk of developing diabetes by only a small amount, but scientists say the combined impact of the collection of genes could be powerful, and the discovery could help develop new forms of prevention and treatment. One of the genes has also been linked to prostate cancer.

Diabetes affects 246 million people worldwide and is expected to affect some 380 million by 2025, according to the International Diabetes Federation website.

In the study, published on Sunday in Nature Genetics, 90 researchers from more than 40 European and US centers pooled genetic data gathered from more than 90,000 people.

"The sort of studies we are doing are designed to pick up common variants," said Mark McCarthy of the University of Oxford, who led the research. "Across these six, some of the variants are in 10 percent [of the population], in other cases the one that's increasing the risk is the majority version that is in 90 percent."

McCarthy said inheriting a disease variant of any of the genes from either parent could increase a person's risk of developing type 2 diabetes by 10 percent - 15 percent.

"There'll be a few individuals who will have many of these risk variants and they'll have higher risk of diabetes than individuals who have been lucky enough to end up with very few."

Since none of the new genes were previously suspected of having a role in diabetes, there is still much work to do in working out what the genes are responsible for, though there are clues.

"Virtually all of the genes [found so far] seem to be impacting on the ability of the beta cells to compensate for insulin resistance," he said.

He added that a particular surprise was that one of the genes found linked to type 2 diabetes was recently shown to play a role in prostate cancer. "One of the most exciting bits of this field is that we're finding lots of unexpected connections that sometimes genes seem to influence diseases that we hadn't previously thought of as connected."

Simon Howell, chairman of Diabetes UK, said: "It's remarkable that we still know so little about such a major condition as type 2 diabetes. By revealing new pathways by which the body normally keeps blood glucose levels under control, this research offers new opportunities for more effective ways of treating and preventing this condition."

The findings are the latest success in a relatively recent technique called the genome-wide association study.

The Guardian

(China Daily 04/01/2008 page10)