In what promises to be a major breakthrough in our understanding of Alzheimer’s disease, an international group of scientists has discovered 11 previously unknown genes that increase people’s risk of developing this most common cause of dementia.

The study, undertaken by the International Genomics Project (IGAP) and co-led by Cardiff University, Wales, UK, is published online this week in Nature Genetics.

The large group of four teams comes from 145 academic centers around the world and comprises most of the world’s experts in the genetics of Alzheimer’s.

They believe the discovery, which now brings the total number of genes known to raise the risk of developing Alzheimer’s disease to 21, will open new avenues of research to improve our knowledge about the mechanisms that underpin the brain-wasting disease.

Prof. Julie Williams, head of neurodegeneration at Cardiff School of Medicine’s Medical Research Council (MRC) Centre on Neuropsychiatric Genetics and Genomics, led one of the four international teams. She says:

“By combining the expertise and resources of geneticists across the globe, we have been able to overcome our natural competitive instincts to achieve a real breakthrough in identifying the genetic architecture that significantly contributes to our mapping of the disease.”

The study builds on genome-wide association analysis work that, since 2009, has found the other 10 genes already known to be linked with Alzheimer’s.

Prof. Williams, who is also chief scientific advisor for Wales, says the biggest surprise was finding out that several of the new genes involve the body’s immune response in causing dementia.

However, she cautions that although we now have details of 21 genes known to increase risk of developing Alzheimer’s, “a large portion of the genetic risk for the disease remains unexplained.”

“Further research is still needed to locate the other genes involved before we can get a complete picture,” she adds.