Identifying genetic risk factors for Alzheimer’s disease is essential if we are to improve our understanding and treatment of it. Progress in human genome analysis along with genome-wide association studies are now leading to major advances in the field. Researchers in Europe, the US and Australia have identified 75 regions of the genome that are associated with Alzheimer’s disease. Forty-two of these regions are novel, meaning that they have never before been implicated in the disease. The findings, published in Nature Genetics, bring new knowledge of the biological mechanisms at play and open up new avenues for treatment and diagnosis.