A set of genes that appear to raise the risk of adult-onset diabetes has been identified, promising a test that can predict who is likely to develop the disease.

An international team of scientists has identified five different genetic variants that are linked to the condition, which is caused both by family inheritance and lifestyle factors such as poor diet, obesity and smoking. The five variants are thought together to account for about 70 per cent of the genetic risk of type 2 diabetes, the form of the disease that generally strikes in adulthood.

The findings are important as they pave the way for a blood test that could be used to identify people who are predisposed to developing diabetes.

Such a test could be used in a screening programme to pick up those who are most at risk, who could then alter their diet and exercise patterns accordingly. Professor Philippe Froguel of Imperial College, London, one of the leaders of the study, said: “The two major reasons why people develop type 2 diabetes are obesity and a family link. Our new findings mean that we can create a good genetic test to predict people’s risk of developing this type of diabetes.

“If we can tell someone that their genetics mean they are predisposed 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 results, which are published in the journal Nature, also point towards at least one potential cause of the disease.

One of the five genes, SLC30A8, is involved in transporting the mineral zinc in the body, and is known to be involved in secreting insulin, a hormone that is important to metabolising sugar.

As type 2 diabetes is associated with an insulin deficiency, it could be possible to treat it by fixing the faulty zinc transporter. “We can also use what we know about the specific genetic mutations associated with type2 diabetes to develop better treatments,” Professor Froguel said.

Diabetes, which affects at least two million people in Britain comes in two forms. In type 1, which accounts for between 5 per cent and 15 per cent of cases and usually starts in childhood, the body cannot make insulin at all, and regular injections of the hormone are needed.

Type 2 diabetes is much more common, accounting for between 85 per cent and 95 per cent of cases, and generally begins after the age of 40. While the body still makes some insulin, it either does not make enough, or the body becomes resistant to its effects.

It is usually linked to obesity, though a family history of the condition is also known to raise the risk. It is not normally treatable with insulin injections or other drugs, and must usually be controlled by switching to a healthier diet or by losing weight.

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