Scientists have identified a genetic variation in people with type 2 diabetes that affects how the body's muscle cells respond to the hormone insulin.

Findings from Imperial College, London, and other international institutions features in Nature Genetics and highlights a new target for scientists developing treatments for diabetes.

Previous studies have identified several genetic variations in people with type 2 diabetes that affect how insulin is produced in the pancreas. This study shows a genetic variation that seems to impair the ability of the body's muscle cells to use insulin to help them make energy.

People with type 2 diabetes can have problems with the body not producing enough insulin and with cells in the muscles, liver and fat becoming resistant to it. Without sufficient insulin, or if cells cannot use insulin properly, cells are unable to take glucose from the blood and turn it into energy. Until now, scientists had not been able to identify the genetic factors contributing to insulin resistance in type 2 diabetes.

In the new research, scientists from international institutions including Imperial College London, McGill University, Canada, CNRS, France, and the University of Copenhagen, Denmark, looked for genetic markers in over 14,000 people and identified four variations associated with type 2 diabetes.

One of these was located near a gene called IRS1, which makes a protein that tells the cell to start taking in glucose from the blood when it is activated by insulin. The researchers believe that the variant they have identified interrupts this process, impairing the cells' ability to make energy from glucose. The researchers hope that scientists will be able to target this process to produce new treatments for type 2 diabetes.

Professor Philippe Froguel, one of the authors of the study, said: "We are very excited about these results – this is the first genetic evidence that a defect in the way insulin works in muscles can contribute to diabetes. Muscle tissue needs to make more energy using glucose than other tissues. We think developing a treatment for diabetes that improves the way insulin works in the muscle could really help people with type 2 diabetes.

"It is now clear that several drugs should be used together to control this disease. Our new study provides scientists developing treatments with a straightforward target for a new drug to treat type 2 diabetes," added Professor Froguel.