Researchers in Iceland say they have identified a single genetic change which could predispose close to 40 percent of the population to type-2 diabetes.
The team led by Kari Stefansson of DeCode Genetics, identified the gene in a study of Iceland's comprehensive genetic records, and found it is carried by 38 percent of the northern European populations studied, and is also common among African-Americans.
Stefansson and colleagues say their finding could help in the development of an easy test for diabetes risk and might also lead to better drugs for the disease.
Diabetes affects nearly 200 million people worldwide and 18 million people in the United States alone.
He says people with one copy of this variant, have a 40% higher risk of developing type-2 diabetes.
Stefansson, a chief executive officer of DeCode says those with two copies of the variant have a 140 percent increase in risk.
He believes if this variant was removed from the population, there would be 20% less of the type-2 diabetes cases in society.
Type-2 diabetes also known as adult-onset diabetes, differs from type-1, or juvenile, diabetes.
The inability to use and produce insulin properly, means sufferers end up with too much glucose in their blood and have high rates of heart disease, blindness, nerve damage and limb loss.
Type-2 diabetes is associated with obesity, overweight and a lack of exercise and is being found in children more commonly worldwide.
Stefansson says it is a disease that occurs at the 'interface of genes and environment'.
The variant Stefansson and his team have found, called TCF7L2, is associated with a younger onset of the condition, and sufferers appear to be thinner than the average type-2 diabetes patient.
Stefansson believes the discovery sheds new light on the biological causes of the disease and could lead to the development of a genetic test for assessing individual risk and developing more personalized and effective prevention strategies.