Genes May Protect Against APOE4 Alzheimer’s Risk

TL;DR

Prime Big Deal Days · Oct 6–7Offer from Amazon

Get comfort and care essentials delivered free — and shop member deals

• Fast, free delivery on millions of items
• Access to Prime Big Deal Days deals on October 6–7
• Prime Video, Amazon Music and more included

Start your free Prime trial →Free trial for eligible customers · Cancel anytime

As an affiliate, we earn on qualifying purchases.Hide

Researchers analyzing genetic data from nearly 450,000 people 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 such as TNS3 and CISD1 as possible avenues for research, but they do not establish protective treatments or prove the genes prevent Alzheimer’s.

Researchers analyzing genetic data from nearly 450,000 people identified 42 DNA regions associated with Alzheimer’s risk among people who carry APOE4, including signals that may help explain why some carriers do not develop the disease. The study, published in Alzheimer’s & Dementia, highlights genes active in oligodendrocytes as possible research targets, but does not show that any gene or treatment can prevent Alzheimer’s.

The team, led by Michael Belloy, an assistant professor at Washington University in St. Louis, examined genetic data from people with one or two APOE4 copies, including carriers who had not developed Alzheimer’s. The researchers reported links to 42 DNA regions: 13 previously identified and 29 newly identified in their analysis. APOE4 is associated with substantially higher risk, but carrying it does not mean a person will inevitably develop the disease.

To explore which brain processes might be involved, the researchers also examined gene activity in post-mortem brain tissue from 424 donors. Many of the genes they considered potentially protective were active in oligodendrocytes, cells that form insulating sheaths around nerve fibers and help support the efficient transmission of signals. The analysis flagged TNS3 and CISD1 as possible risk modifiers: TNS3 is involved in oligodendrocyte maturation and survival, while CISD1 is involved in their metabolism.

The researchers and outside experts described these findings as leads, not established mechanisms. The study does not show that raising the activity of these genes would lower Alzheimer’s risk in people. The report also noted a possible signal involving MAPT, which encodes the tau protein, but experts cautioned that tissue collected after death in later disease stages may not reflect what happens earlier.

Oligodendrocytes Become a Research Lead

The findings could broaden Alzheimer’s research beyond APOE4 itself. If further work confirms that oligodendrocyte biology helps modify risk, it may point researchers toward cellular processes that have received less attention as potential treatment targets. That could matter because APOE4 is a powerful risk factor, yet outcomes vary among carriers.

Belloy told Being Patient that the results suggest a set of genes may counter risk associated with APOE4 and that oligodendrocytes may be a useful focus for future therapies. The possible targets are not ready for clinical use: the report says there are no FDA-approved medicines targeting TNS3 or CISD1 that can be repurposed for Alzheimer’s. Any treatment idea would require further laboratory research, safety testing and clinical trials.

The work may also help scientists understand why genetic risk is not destiny. It identifies possible biological differences among APOE4 carriers, but does not provide an individual risk prediction or a basis for changing anyone’s care. The results are most relevant as a direction for research into disease mechanisms and future drug development.

APOE4 Raises Risk, Not Certainty

APOE4 is widely recognized as the strongest common genetic risk factor for Alzheimer’s, but its effect varies. The Being Patient report says people with two copies have elevated risk and cites an estimate that about 60 percent of people with two copies develop Alzheimer’s over their lifetime. That estimate also underscores that a substantial share do not, motivating studies of genetic factors that may alter risk.

Researchers have previously investigated protective genetic variants, including the Christchurch variant, after a woman with an inherited form of Alzheimer’s remained cognitively healthy until her 70s. The report notes that later investigation of whether one copy of that variant is protective has faced questions about the reliability of some studies. The current research examines a different set of genetic signals among APOE4 carriers and should not be treated as confirmation of earlier findings.

Genetic studies can identify associations, but they do not by themselves establish how a gene causes protection or whether changing its activity would benefit patients. This study also combined genetic data with gene-activity information from donated brain tissue, giving researchers clues about cell types while leaving questions about timing and disease processes unresolved.

“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

Key Findings Still Need Validation

Several limitations leave open whether the signals will hold up and apply broadly. According to the report, most participants were of European ancestry, so researchers do not yet know whether the findings generalize to other ancestry groups. The analysis also included people with a clinical Alzheimer’s diagnosis, but only 40 percent had biomarker confirmation; some diagnoses could have been incorrect.

The brain-tissue analysis used samples from donors who had died, potentially during later stages of disease. Nisenbaum told Being Patient that this may make the data a poor guide to gene activity earlier in the disease course. It also remains unknown how much any individual gene contributes to risk, whether the signals reflect direct protection, and whether they can be safely targeted with drugs.

The study identifies associations, not proof of prevention. No result described in the report establishes that APOE4 carriers can reduce their personal risk by changing gene activity, and no treatment based on these proposed targets is reported as available.

Validation Before Treatment Tests

The immediate next step is experimental and validation research, as Belloy said. Researchers will need to test whether the identified genetic signals can be replicated, examine how the implicated genes affect oligodendrocytes and other brain processes, and determine whether those effects influence Alzheimer’s risk.

Further studies in populations with a broader range of ancestries and analyses that better confirm Alzheimer’s diagnoses could help establish how widely the results apply. If particular genes prove to be meaningful and safely modifiable, drug-development work could follow. The report does not give a timeline for that work or announce a clinical trial targeting TNS3 or CISD1; any potential therapy remains a future possibility.

Key Questions

What did the study find about APOE4 and Alzheimer’s?

Researchers reported 42 DNA regions associated with Alzheimer’s risk among APOE4 carriers, including 29 newly identified in their analysis. The findings suggest other genetic factors may modify APOE4-associated risk, but do not prove that the identified genes prevent disease.

Which genes did the researchers highlight?

The report identifies TNS3 and CISD1 as possible risk modifiers linked to oligodendrocytes. It also describes a possible protective association involving MAPT activity, while noting that the interpretation is uncertain and needs more study.

Does carrying APOE4 mean someone will develop Alzheimer’s?

No. APOE4 raises Alzheimer’s risk, but it does not determine an individual’s outcome. The report cites an estimate that about 60 percent of people with two copies develop Alzheimer’s over their lifetime, meaning many do not.

Can people take a medicine based on these findings?

The report does not identify an approved medicine targeting TNS3 or CISD1 for Alzheimer’s. The findings are research leads, and further validation and testing would be needed before a treatment could be considered.

Source: rss