Gene linked to type 2 diabetes

Icelandic researchers have identified a gene they say could be involved in up to a fifth of all cases of type 2 diabetes. People who inherit a particular version of the gene have a significantly increased risk of developing the condition, say the scientists, who are based at the biotechnology company deCODE Genetics. The findings, published in the journal Nature Genetics, could lead to the improved prevention and treatment of diabetes.

Type 2 diabetes (T2D) usually affects people over the age of 40. It is more common in overweight, inactive people, and those with a family history of the disease, which suggests that genetic factors are also involved. People with diabetes cannot regulate their blood sugar levels properly, either because their pancreas is not making enough insulin, or because the body becomes resistant to its effects.

In the latest study, the researchers looked at DNA from more than 2000 patients and healthy controls, living in Iceland, Denmark and the US. They focused on different versions of a gene called TCF7L2, which makes a protein that has previously been linked to the control of blood sugar levels. The scientists identified one particular variant of the gene that is more common in people with T2D than in unaffected people. Those who inherit one copy of the gene variant have a 45 per cent increased risk of developing the disease, whereas people who inherit a double dose have a 140 per cent higher chance of doing so, say the scientists.

Team leader Kari Stefansson, chief executive of deCODE, called the findings 'a milestone in human genetics', adding 'a common gene variant conferring elevated risk of T2D has been earnestly sought by the genetics community for many years'. He also said the discovery was 'an exciting starting point for the development of new drugs', and that his company was actively pursuing the development of new diagnostic and therapeutic products for the condition. US medical geneticist David Altshuler commented that 'in terms of the epidemiological risk of diabetes, this is by far the biggest find to date'.