'Significant step' in Alzheimer's disease DNA research
28 October 2013 Last updated at 09:45 GMT
Scientists from Wales have helped develop a clearer picture of what causes Alzheimer's disease after the largest ever analysis of patients' DNA.
It has been described as a "major breakthrough" in the understanding of the disease.
It is hoped that the research, jointly led by a team at Cardiff University, will pave the way for new treatments.
Prof Julie Williams, from Cardiff University, explained what the findings mean.