An international team of scientists has made a breakthrough which could help halt the growth of diabetes.

Researchers from Britain and Canada have identified the gene that causes diabetes, which means potential sufferers could be tested to assess their risk of developing the disease.

It is hoped the discovery will also help develop new treatments for adult onset, or type 2 diabetes, which is one of the most common illnesses among middle aged and older people in the UK.

In Scotland, around 150,000 people suffer type 2 diabetes while another 60,000 are estimated to have the disease but are unaware. The number of people with the illness is expected to increase by half over the next decade.

The research, published online in the science magazine, Nature, is the first time the genetic make-up of any disease has been mapped in such detail.

If adult diabetes is not properly managed, patients can suffer severe complications, such as blindness, amputations and kidney disease, and are at far higher risk of developing heart disease or suffering a stroke.

The researchers at McGill University, Montreal, and Imperial College London, believe their findings explain up to 70% of the genetic background of type 2 diabetes.

In addition, one of the genetic mutations they detected may further explain the causes behind the disease, potentially leading to a new therapy.

Lead researcher Dr Constantin Polychronakos, of McGill University, said: "The rapidly increasing prevalence of type 2 diabetes is believed to be due to environmental factors, such as increased availability of food and decreased opportunity and motivation for physical activity, acting on genetically susceptible individuals."

The study revealed people with the disease have a mutation in a particular zinc transporter known as SLC30A8, which is involved in regulating insulin secretion.

Type 2 diabetes is caused by a deficiency in insulin and the researchers believe it may be possible to treat it by fixing this transporter.

Professor Philippe Froguel, of Imperial College London, said: "The two major reasons why people develop type 2 diabetes are obesity and a family link. Our new findings mean we can create a good genetic test to predict people's risk of developing this type of diabetes.

"If we can tell someone their genetics mean they are pre-disposed towards type 2 diabetes, they will be much more motivated to change things such as their diet to reduce their chances of developing the disorder."

The scientists reached their conclusions after comparing the genetic makeup of 700 people with type 2 diabetes and a family history of the condition, with 700 controls. They looked at mutations in the building blocks, called nucleotides, which make up DNA.

There are mutations in about one in every 600 nucleotides and the scientists examined more than 392,000 of these to find the ones specific to type 2 diabetes.

Professor David Balding, epidemiologist at Imperial College, said: "Our research shows this technology can generate big leaps forward. The task now is to study the genes identified in our work more intensively, to understand more fully the disease processes involved, devise therapies for those affected and to try to prevent future cases."