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Researchers analyzed genetic data from nearly 450,000 people and identified 42 DNA regions associated with Alzheimer’s risk among people carrying APOE4, including 29 regions not previously reported in this analysis. The findings point to oligodendrocytes and genes including TNS3 and CISD1 as possible avenues for research, but they need further validation and do not establish a treatment or guarantee protection.
Researchers analyzing genetic data from nearly 450,000 people identified 42 DNA regions associated with Alzheimer’s risk among people carrying one or two copies of APOE4, the strongest common genetic risk factor for the disease. The study, published in Alzheimer’s & Dementia, points to genes active in oligodendrocytes as possible modifiers of risk, but the findings are early research, not evidence that any gene can reliably prevent Alzheimer’s.
The team, led by Michael Belloy, an assistant professor at Washington University in St. Louis, focused on genetic differences that might help explain why some APOE4 carriers develop Alzheimer’s while others do not. APOE4 raises risk, but does not determine an individual’s outcome. The study identified 42 DNA regions linked to Alzheimer’s risk in relation to APOE4 status: 13 had been reported previously and 29 were new in this analysis.
The researchers also examined gene activity in post-mortem brain tissue from 424 donors. Several candidate protective genes were active in oligodendrocytes, cells that form insulating sheaths around nerve fibers and help electrical signals travel between neurons. Belloy highlighted TNS3, which is involved in oligodendrocyte maturation and survival, and CISD1, which is involved in the cells’ metabolism.
The analysis also raised questions about MAPT, the gene that encodes tau. Laura Nisenbaum, chief scientific officer of the Alzheimer’s Drug Discovery Foundation and not involved in the study, told Being Patient that higher MAPT activity appearing protective was intriguing. She said the result may be relevant to diranersen, a tau-lowering gene-silencing therapy described in the report as heading toward Phase 3 trials. The study itself does not show that diranersen, or any other treatment, prevents disease in APOE4 carriers.
Oligodendrocytes Offer a Research Lead
The findings could broaden the search for Alzheimer’s treatments beyond genes and processes already under close study. If further work confirms that oligodendrocytes help modify risk associated with APOE4, researchers may investigate whether supporting these cells or the pathways involving TNS3 and CISD1 can alter disease processes.
That possibility remains a research direction, not a clinical option. The source report says there are currently no FDA-approved medications targeting TNS3 or CISD1 that can be repurposed for Alzheimer’s. Belloy told Being Patient that individual genes may have small effects, while combinations of targets could be worth investigating. Whether changing the activity of these genes would reduce disease risk or improve outcomes has not been established.
For readers, the key distinction is that APOE4 is a risk factor, not a diagnosis or certainty of future illness. The study offers clues about why risk may differ among carriers, but it does not provide a personal risk estimate or a proven prevention strategy. Decisions about genetic testing or health care should be discussed with a qualified professional.
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How the APOE4 Study Was Built
APOE4 is widely recognized as a major common genetic risk factor for Alzheimer’s, but many other genetic and biological factors can affect whether and when the disease develops. Belloy’s group used that variation as a starting point, looking for genetic signals among carriers that might be associated with a different outcome. The report says that lifetime risk is not inevitable even for people with two APOE4 copies; it cites an estimate that about 60 percent of people with two copies develop Alzheimer’s over their lifetimes.
To connect genetic signals with possible biology, the team compared its risk analysis with gene-activity data from donated brains. That step can suggest which cell types warrant further study, but post-mortem tissue is a snapshot from after death. Nisenbaum cautioned that the samples came from people who died during later stages of disease and may not reflect what happens earlier. This limits how confidently researchers can interpret the timing and role of the observed gene activity.
Other reported genetic research has examined people with unusual resistance to inherited Alzheimer’s, including a Colombian woman whose disease-causing mutation typically leads to symptoms at a younger age. The source report describes two copies of the Christchurch variant as part of the explanation for her delayed symptoms, while also noting that later research has cast doubt on some findings about the variant. That separate work provides context for studying genetic protection but does not validate the genes in Belloy’s study.
“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 study’s signals are associations; they do not prove that the identified genes cause protection or that changing their activity would prevent Alzheimer’s. Belloy said further experimental work and independent validation are needed. The source report also notes that most participants were of European ancestry, so it is not clear whether the results apply to other populations.
There are additional limits to the underlying data. Participants had a clinical diagnosis, but only about 40 percent had biomarker confirmation, leaving open the possibility that some diagnoses were incorrect. The post-mortem gene-activity data came from 424 donors and may not capture earlier disease stages. The report does not give effect sizes for the candidate genes or establish how much they change risk for an individual carrier.
It is also not yet clear whether the candidate genes can be safely and effectively targeted in people, or whether any of the observed signals will lead to a therapy. The findings should not be read as evidence that APOE4 carriers can avoid Alzheimer’s through a particular behavior or intervention.
Validation Before Treatment Tests
The next steps are further genetic validation and experimental studies to test whether the candidate pathways play a causal role in disease risk. Researchers would also need to examine the findings in populations with different ancestries and clarify whether the signals hold when Alzheimer’s diagnoses are confirmed with biomarkers.
Any treatment development would require additional evidence that a target such as TNS3 or CISD1 can be altered safely and that doing so changes meaningful outcomes. The report mentions diranersen’s planned progression toward Phase 3 trials as a separate tau-focused development; it does not establish that the new study’s MAPT finding predicts the therapy’s success. No timeline for follow-up studies of the candidate genes is specified.
Key Questions
Does carrying APOE4 mean someone will develop Alzheimer’s?
No. APOE4 raises risk, but it does not make Alzheimer’s inevitable. The source report says about 60 percent of people with two copies develop the disease over their lifetimes, meaning the gene is not a certain prediction for an individual.
Which genes did the study identify as possible risk modifiers?
The researchers highlighted TNS3 and CISD1 as candidates linked to oligodendrocyte biology. They also reported a finding involving MAPT gene activity. These are research leads, not proven protective genes or treatment targets.
Can these findings be used to prevent Alzheimer’s now?
No. The study did not test a prevention treatment, and the candidate genetic signals need further validation. The report says no FDA-approved medications target TNS3 or CISD1 for repurposing in Alzheimer’s.
Do the results apply to all ancestry groups?
That is not yet clear. Most participants were of European ancestry, according to the report, so additional research is needed to see whether the findings generalize to other populations.
Source: rss
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