A comprehensive international genetics study found several new genetic risk factors for Alzheimer’s disease and related dementias, providing one of the clearest pictures of the biological pathways that cause the devastating neurodegenerative disorder.
Published in the journal Nature Genetics, the study combined data from 978,514 people of European ancestry, including over 128,681 individuals with Alzheimer’s disease and related dementias (ADRD). The researchers found 91 regions of the genome linked to dementia risk, including 16 new loci that had not been linked to Alzheimer’s in European populations.
The project brought together several major research consortia, including the European Alzheimer and Dementia Biobank, the International Genomics of Alzheimer’s Project, and the Psychiatric Genomics Consortium. By pooling results from 52 studies, scientists created one of the largest and most comprehensive genome-wide association analyses ever conducted for Alzheimer’s research.
Although aging is the strongest risk factor for Alzheimer’s disease, which affects tens of millions of people worldwide, genetics plays a major role in disease development. The APOE ε4 gene is known to strongly increase Alzheimer’s risk, but scientists believe many additional genes contribute smaller effects that together shape vulnerability.
The new study significantly expands that genetic map. Newly identified risk regions include genes involved in immune signaling, lipid metabolism, and cellular waste disposal—processes already suspected to contribute to the buildup of amyloid plaques and tau tangles, the hallmark pathologies of Alzheimer’s disease.
Several of the newly discovered loci, including SRC, PTPRC, MGAT5, and DOCK4, point toward the importance of microglia, the brain’s immune cells. Previous studies have suggested that dysfunctional immune responses may accelerate neurodegeneration by impairing the brain’s ability to clear toxic proteins.
Researchers also found evidence that many Alzheimer’s-associated genes are highly active in microglia across multiple brain regions, reinforcing the idea that inflammation and immune regulation are central to disease progression.
To distinguish true Alzheimer’s signals from broader dementia-related effects, the team performed additional analyses excluding “proxy” cases—individuals reporting a parent or sibling with dementia—and excluding large biobank datasets based primarily on medical coding. Even under these stricter conditions, 56 of the identified loci remained strongly associated with clinically diagnosed Alzheimer’s disease, suggesting the findings are robust.
Beyond identifying genes, the researchers tested how combined genetic risk influences brain pathology. They created polygenic risk scores using Alzheimer’s-associated variants other than APOE and examined their relationship to postmortem brain changes.
Individuals in the highest 10% of genetic risk had roughly double the likelihood of severe tau tangles and amyloid plaque buildup compared with people in the middle-risk group. Conversely, individuals in the lowest 10% had substantially reduced risk.
Importantly, the genetic scores were more strongly linked to classic Alzheimer’s pathology than to other forms of brain damage such as strokes or vascular disease. This suggests that many of the identified variants specifically contribute to Alzheimer’s biological mechanisms rather than dementia in general.
Despite the scale of the study, researchers caution that genetics alone cannot fully predict who will develop Alzheimer’s. The polygenic scores explained only a modest portion of disease variability, highlighting the continued importance of environmental and lifestyle factors.
Still, scientists say the findings could help accelerate the search for new drug targets and improve future risk prediction tools. The study also emphasizes the necessity of larger and more diverse datasets, as the current analysis focused primarily on individuals of European ancestry.
Future work will examine how rare genetic variants and structural changes in DNA contribute to Alzheimer’s biology, potentially paving the way to precision medicine and earlier intervention.
The post Alzheimer’s Genetic Risk Loci: 16 New Candidates appeared first on Inside Precision Medicine.