Diabetes gene found in 40% of population

Jan 16 2006

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.

He says it is also a starting point for the discovery of new drugs, and they are actively pursuing the development of both diagnostic and therapeutic products to better prevent and treat T2D.

The researchers studied in the main northern Europeans, but say they saw other variants that are found in people around the world that also confer diabetes risk.

DeCode specializes in trolling the country's DNA database for information.

Virtually the entire population of Iceland, a highly inbred group, has voluntarily donated DNA to be sequenced, analyzed and published.

The DeCode team found the gene first in Icelanders with diabetes, and then looked in 228 Danish women with type-2 diabetes and 539 who did not have the condition.

They also looked at 361 American diabetics of European descent and 530 similar people without diabetes.

They repot that the TCF7L2 gene can be found on chromosome 10q, and is a gene that controls another gene, in this case the well-known Wnt signaling pathway.

Wnt is involved in key developmental and growth regulatory mechanisms of cells.

The study is published in the journal Nature Genetics.