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Researchers analyzed genetic data from nearly 450,000 people and identified 42 DNA regions associated with Alzheimer’s risk among APOE4 carriers, including 29 not previously reported in this analysis. The findings point to oligodendrocytes and genes such as TNS3 and CISD1 as possible research targets, but the results need validation and do not establish a treatment or an individual’s protection.
Researchers analyzing genetic data from nearly 450,000 people identified 42 DNA regions associated with Alzheimer’s risk among APOE4 carriers, including signals that may help explain why some people with the risk variant do not develop the disease. The study, published in Alzheimer’s & Dementia, highlights genes active in oligodendrocytes as possible leads for future research, but it does not show that those genes can prevent Alzheimer’s or provide a treatment.
Michael Belloy, an assistant professor at Washington University in St. Louis, and colleagues focused on people who carried one or two copies of APOE4 but had not developed Alzheimer’s. APOE4 is a major common genetic risk factor; the source report says it can raise risk roughly four- to 12-fold. The study looked for other genetic differences that might modify that risk.
The researchers identified 42 DNA regions linked to APOE4-related risk: 13 had been identified previously, while 29 were new in this analysis. They also examined gene activity in post-mortem brain tissue from 424 donors. Several genes associated with protection were active in oligodendrocytes, cells that form insulating sheaths around nerve fibers and support efficient signaling between neurons.
Belloy identified TNS3 and CISD1 as possible risk modifiers. TNS3 is involved in oligodendrocyte maturation and survival, while CISD1 has a role in their metabolism. The findings make these genes candidates for further investigation, not proven protective factors. The report says no FDA-approved medicines target them for Alzheimer’s that could be repurposed for this purpose.
Oligodendrocytes Emerge as Research Leads
The results add to evidence that APOE4 does not determine a person’s outcome on its own. Identifying biological factors associated with lower risk could help researchers understand how the disease develops and where future therapies might act. In this study, the concentration of signals in oligodendrocytes suggests that cells supporting nerve communication may deserve more attention alongside other areas of Alzheimer’s research.
That is a research direction, not a clinical finding that people can use to estimate their personal risk. Belloy told Being Patient that individual genes may have small effects, while targeting several pathways might eventually produce larger benefits. Whether that can be achieved safely or effectively with a drug remains untested. The findings also do not establish that increasing activity of TNS3 or CISD1 would prevent disease.
The study’s analysis of MAPT activity also drew attention because MAPT encodes tau, a protein that forms tangles in Alzheimer’s. Laura Nisenbaum, chief scientific officer of the Alzheimer’s Drug Discovery Foundation and not involved in the research, said the observation was intriguing. The report notes a possible connection to diranersen, a gene-silencing therapy being developed to lower tau, but the study does not test that drug or show that its approach would benefit APOE4 carriers.
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How Researchers Searched for Protection
APOE4 is associated with increased Alzheimer’s risk, but carrying it does not guarantee that someone will develop the disease. The Being Patient report says that, over a lifetime, about 60 percent of people with two APOE4 copies develop Alzheimer’s. The remaining cases have prompted researchers to look for other genetic influences that may alter risk.
This work follows earlier research into genetic variants associated with protection, including the Christchurch variant. The source report describes a Colombian woman with an inherited form of Alzheimer’s who remained cognitively healthy until her 70s after inheriting two copies of that variant. It also notes that later investigation has questioned the reliability of some studies on Christchurch protection, a reminder that such findings require careful replication.
More broadly, genetics research is helping identify possible pathways for drug development, while gene-silencing and gene-editing technologies are being studied in trials. The current study’s contribution is a set of candidate regions and cell types for follow-up, rather than a tested prevention strategy.
“Ultimately, we found a set of genes that look promising to counter Alzheimer’s disease risk due to APOE4.”
— Michael Belloy, assistant professor at Washington University in St. Louis, speaking to Being Patient
Findings Need Broader Validation
The genetic signals remain candidates requiring validation. Most participants were of European ancestry, so it is not clear whether the results apply to people from other ancestry groups. The report also says participants had clinical Alzheimer’s diagnoses, but only about 40 percent had biomarker confirmation; some diagnoses may therefore have been incorrect.
The brain-tissue analysis has a separate limitation: tissue came from donors after death, including people who had reached later disease stages. Nisenbaum cautioned that this may not reflect what happens earlier in Alzheimer’s. The study cannot establish when the identified genes act, how large their effects are, or whether changing their activity would alter disease risk.
Nor does the analysis provide a clinical genetic test for protection. It does not show that a person carrying a particular variant will avoid Alzheimer’s, or that someone without an identified signal is certain to develop it. The source report gives no treatment results from this work.
Replication Before Treatment Claims
The next steps are experimental testing and replication in additional groups, including people with ancestry backgrounds underrepresented in the study. Researchers would also need to establish whether the candidate genes influence risk directly, identify the relevant timing and cell processes, and test whether those processes can be safely altered.
Belloy told Being Patient that further validation is needed. For now, the reported findings serve as a map for research rather than a basis for changing clinical care. No approved Alzheimer’s medicine targeting TNS3 or CISD1 was identified in the source report, and the study does not establish that diranersen or another tau-targeting approach would work because of these results.
Key Questions
Does carrying APOE4 mean a person will develop Alzheimer’s?
No. APOE4 is associated with higher risk, but it does not determine an individual outcome. The source report says about 60 percent of people with two copies develop Alzheimer’s over their lifetime.
Which genes did this study highlight?
The researchers highlighted TNS3 and CISD1 as possible risk modifiers and reported other genetic regions associated with APOE4-related risk. These are research candidates, not confirmed protective genes for clinical use.
Do the findings mean there is a new treatment for APOE4 carriers?
No. The study identified genetic associations and possible biological pathways; it did not test a treatment. The source report says there are no FDA-approved medicines targeting TNS3 or CISD1 for Alzheimer’s that could be repurposed for this purpose.
Can the results be applied to everyone?
That is not yet clear. Most participants were of European ancestry, and researchers need to test whether the findings hold in other populations. Some diagnoses in the genetic data also lacked biomarker confirmation.
Source: rss
