An international team of researchers has made significant progress in understanding the genetic basis of Alzheimer's disease, identifying 91 genetic loci associated with the risk of developing the disease and related dementias, 16 of which were previously unknown.

The findings, published in Nature Genetics on June 3, 2026, represent one of the largest genetic studies of Alzheimer's to date, relying on analysis of genetic data from nearly one million people, providing a more comprehensive view of the genetic factors contributing to the disease's development.

Largest study of its kind

Alzheimer's disease is the most common cause of dementia worldwide, affecting millions of people, while its exact causes remain incompletely understood. Scientists believe the disease results from a complex interaction between genetic and environmental factors. To unravel this complexity, researchers gathered data from over 128,000 people with Alzheimer's and approximately 850,000 without the disease, all of European ancestry.

The study also involved a group of the largest international research consortia and specialized biobanks focused on dementia. The research was conducted as a collaborative effort including major international consortia such as the European Alzheimer and Dementia Biobank (EADB), the Alzheimer's Disease Genetics Consortium (ADGC), and the FinnGen project. The study was carried out by an international team of scientists from at least 15 countries in Europe and North America, bringing together many of the world's largest Alzheimer's genetics research consortia. By integrating results from 52 independent studies and several major biobanks, scientists were able to map the genetic regions associated with the disease more accurately.

Discovery of 16 new genetic regions

The study identified 91 genetic loci associated with the risk of Alzheimer's and related dementias, including 16 loci linked to the disease for the first time. Of these, 56 loci were directly associated with clinically diagnosed Alzheimer's, while others require further studies to confirm their role.

The findings indicate that Alzheimer's is not caused by a single gene or a limited number of genes, but is a polygenic disease, with dozens of small genetic variants cumulatively increasing the risk.

Brain immune cells and neuroinflammation

The study showed that many of the discovered genetic loci are associated with biological pathways known to play a role in disease development, including the accumulation of beta-amyloid protein plaques and the formation of tau protein tangles, the two hallmark features of Alzheimer's.

However, the results also highlighted the importance of the brain's immune system. Researchers found that many of the risk-associated genes are particularly active in microglia, the brain's primary immune cells.

This discovery strengthens the growing evidence that neuroinflammation and abnormal immune responses may be key drivers of disease progression rather than merely a consequence.

The study also revealed significant associations with lipid metabolism and cellular systems responsible for protein recycling and waste disposal within neurons.

New tool for estimating risk

Based on the discovered genetic loci, researchers developed a polygenic risk score, a tool that combines the effects of dozens of genetic variants to estimate an individual's likelihood of developing the disease.

The results showed that people with the highest genetic risk scores were approximately twice as likely to develop severe Alzheimer's-related brain changes, including beta-amyloid plaque accumulation and advanced tau tangles, compared to those with moderate risk.

Although the predictive power of this tool remains limited, it represents an important step toward early identification of people at the highest risk before clinical symptoms appear.

Toward personalized medicine for Alzheimer's

Researchers believe that this study provides one of the most comprehensive genetic maps of Alzheimer's to date, opening the door to a deeper understanding of the biological mechanisms driving neurodegeneration.

The findings are expected to help identify new drug targets, improve early diagnostic tools, and develop more precise treatment strategies based on each patient's genetic profile.

Scientists emphasize that the next step involves expanding studies to include more diverse populations, along with collecting more detailed clinical data to understand the exact role of the discovered genetic loci and how they contribute to disease progression.

As progress in genomics continues, researchers hope these discoveries will accelerate efforts to prevent and treat Alzheimer's, shifting medical care from a general approach to personalized medicine based on each individual's genetic fingerprint.