A groundbreaking study has found two new genes which could be linked to Alzheimer's.
Until now, these genes were seen as protectors, since they are part of the brain's immune system.
However, scientists at Cardiff University have demonstrated that they can also create fertile ground for the neurodegenerative disease.
Crucially, they said there are clear ways to target these genes - potentially blocking them from triggering dangerous activity.
Until now, these two genes were seen as protectors, since they are part of the brain's immune system. But Cardiff University scientists have found they can also facilitate the disease
Dr Doug Brown, director of research and development at the Alzheimer's Society which jointly funded the work, said: 'Over 60 percent of people with dementia have Alzheimer's disease, yet despite its prevalence we still don't fully understand the complex causes of the disease.
'The discovery of two new risk genes for Alzheimer's is an exciting advance that could help to deepen our understanding of what happens in the brains of people with the disease.
'These genes reinforce a critical role for special cells in the brain - called microglia - that are responsible for clearing up debris including damaged cells and proteins.'
Dr Brown said such findings helped to show researchers where to focus their efforts in the search for new, effective treatments.
The researchers from Cardiff University received funding from the Medical Research Council (MRC), Welsh Government and Alzheimer's