A significant Alzheimer’s study is shedding new light on a protective gene that appears to delay the disease in those destined to develop it.

Researchers from two Mass General Brigham hospitals — Mass Eye and Ear and Massachusetts General Hospital — have been studying a large extended family in Colombia with multiple members who have the Paisa mutation, which predicts an extremely high genetic risk of developing early-onset Alzheimer’s disease.

Most people with the Paisa variant develop mild cognitive impairment in their 40s, develop dementia in their 50s and die from complications of dementia in their 60s, according to a press release.

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Among more than 1,000 high-risk family members, 27 of them who have one copy of a rare gene variant — the APOE3 gene, known as Christchurch — reported a delayed onset of symptoms.

On average, they developed signs of Alzheimer’s five years later than those who did not have the variant, the researchers found.

By comparison, the drugs currently available for Alzheimer’s slow the disease's progression by only around six months.

The study findings, published Wednesday in The New England Journal of Medicine, could have important implications for drug development.

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This is a follow-up to a 2019 study in which a woman from the same family who had two copies of the protective APOE3 Christchurch variant did not experience any disease symptoms until her 70s — decades later than the average age of onset, 44.

Joseph F. Arboleda-Velasquez, M.D., PhD, an associate scientist at Mass Eye and Ear who worked on the study, is originally from Colombia, where he spent years studying that woman’s case as part of his medical training.

"It really took the world by storm, the Colombian woman who beat Alzheimer's — it was an amazing discovery," he told Fox News Digital.

"But also, we had to be very careful. Was it really true? Could it be reproduced? It would be amazing if we could develop treatments that replicate the effect of the Christchurch variant, but we didn’t have enough evidence."

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"So, back then, we started this very extensive project of trying to find more individuals who also had Christchurch to see if they were also protected."

In this latest study, researchers analyzed 1,077 descendants of the Colombian family, narrowing the focus to the 27 people who carried both the Paisa mutation and one copy of the protective Christchurch variant.

On average, these 27 family members began showing signs of cognitive impairment at age 52 — compared to age 47 for those without the Christchurch variant.

For two of the individuals, imaging scans showed reduced signs of tau and amyloid plaques, the proteins that build up in the brains of Alzheimer’s patients, the press release stated.

While the original woman might have been dismissed as a "one-time wonder," said Arboleda-Velasquez, this new study provides more evidence that could help support building a drug development program.

"Now, instead of one person, we have 27 more men and women — some who work, some who are retired, some in rural areas, some in the city — who all have the Christchurch variant and are all protected," he said.

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"And now we can move forward with trying to develop therapies that do exactly the same thing."

He added, "This could really transform lives — not just of the individual, but at the population level."

The study did have some limitations, the researchers acknowledged.

It analyzed a relatively small number of people carrying both the Paisa and Christchurch variants, all belonging to a single (albeit large) family. 

Additional studies including larger, more diverse groups are needed to confirm the variant’s protective effect and determine the targets of potential treatments, researchers said.

Some experimental therapies are already being developed, Arboleda-Velasquez noted.

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"A lot of people were very intrigued by the initial Christchurch finding [in 2019], and now this is different," he said. 

"This is a call to action — a call to make drugs that can leverage this discovery."