May 2006

Biotechnology

New publications, experiments, and breakthroughs in biotechnology -- and what they mean.

By TR Editors

Found: A Gene for Diabetes
A common gene variant behind many cases of type 2 diabetes

Source: "Variant of Transcription Factor 7-like 2 (TCF7L2) Gene Confers Risk of Type 2 Diabetes"
S. F. Grant et al.
Nature Genetics 38(3): 320-323

Results: Scientists at deCode Genetics in Iceland identified a gene variant that accounts for more than 20 percent of cases of type 2 diabetes. About 30 percent of Americans carry the gene variant; those who have one copy have a 45 percent greater risk of developing type 2 diabetes, while for those who have two copies (about 7 percent of the U.S. population), the risk is 141 percent greater. The gene, called TCF7L2, regulates the activity of other genes, and the protein it codes for is involved in a biochemical pathway believed to play a role in the maintenance of proper glucose levels.

Why it matters: Scientists have long sought genetic mutations that boost the risk of type 2 diabetes. But the complexity of the disease, which is linked to both environmental and genetic factors, makes the task difficult. The gene identified by deCode is the best genetic predictor of the disease found to date and may point the way to new drug targets.

Methods: DeCode scientists looked at 228 variable genetic markers on a previously identified region of chromosome 10 among 2,000 diabetes patients and controls in Iceland. They identified one version of one marker that correlated with an increased risk of diabetes. They then confirmed the findings in an American and a Danish population.

Next steps: DeCode scientists now plan to develop a genetic test for the variant, which would allow at-risk people to modify their diets and lifestyles long before they develop diabetes. They also plan to search for new drug targets within the biochemical pathway implicated by the gene.