Scientists have identified dozens of previously unknown genetic risk factors for Alzheimer’s disease in one of the largest studies into the condition to date. The findings offer new clues about brain cells and biological processes that could contribute to the disease. The study, which pooled data from 30 research groups, analyzed genetic data from approximately 2.8 million people, including 183,620 with an Alzheimer’s diagnosis.
Researchers identified 127 regions in human DNA associated with the risk of developing the disease, 48 of which had not yet been discovered in this context. One of the study's authors, Emil Uffelmann of Vrije Universiteit Amsterdam in the Netherlands, told Newsweek: "We identified 48 new regions of the genome linked to Alzheimer’s disease risk, and our results point to microglia, the brain’s immune cells, as well as specific types of neurons. These findings provide clues about biological mechanisms that could become therapeutic targets.
"Our study also shows that common genetic variants contribute substantially more to Alzheimer’s disease risk than previously estimated, which means large genetic studies still have more to find. Better genetic risk prediction is promising, but for now it remains a research tool, not a clinical one." Published in Nature and led by Norway's University of Oslo and Oslo University Hospital in collaboration with an international consortium, the research gives scientists a more detailed picture of the biology underlying Alzheimer’s and identifies potential avenues for future treatments. One major finding strengthens evidence for the role of microglia, immune cells that help clear harmful substances and damaged cellular material from the brain.
Researchers found genetic evidence involving microglial activation and immune-cell recruitment. The study also identified genes linked to important brain processes, including evidence of involvement in the processing of amyloid, which is a protein that can accumulate in the brain after Alzheimer’s onset. Following this, researchers also identified, for the first time, several specific types of neurons enriched for genetic signals associated with Alzheimer’s risk, opening another avenue for investigating how the disease develops.
The findings also suggest common genetic variants account for around 16 percent of differences in Alzheimer’s risk between people, nearly three times previous estimates of about 5 percent. Researchers said the higher figure largely resulted from a statistical method that better accounts for APOE, a gene with an unusually large influence on Alzheimer’s risk. That 16 percent figure applies at the population level, and it does not mean genes cause 16 percent of an individual’s Alzheimer’s risk, nor can a genetic test determine whether someone will develop the disease.
Age, environment and other biological and personal factors also influence risk. Edmundo Rodriguez-Frias, a medical contributor at Retreat of Broward in Florida, told Newsweek that genes are a gateway to understanding Alzheimer’s disease. "Genetic variation may modulate corresponding protein levels and point to the role of these variants in disease pathophysiology," Rodriguez-Frias said.
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