A new genetic test could identify people who are most at risk of Alzheimer’s disease when they are just 35 years old.

Scientists in the US are developing a way to predict which people are likely to develop dementia, decades before any of the symptoms emerge.

Although there are currently no treatments for dementia, most drugs in development aim at slowing down symptoms so catching the disease early is crucial. People at most risk could also make lifestyle changes, such as exercising more regularly and eating more healthily.

The test, developed by Massachusetts General Hospital, involves combining all the gene variants which are currently known to raise the risk of Alzheimer’s.

When looking at people with mild cognitive impairment they discovered that the higher people scored on the genetic test, the more likely they were to go onto develop full-blown dementia.