Health

Some Alzheimer's cases may be caused by copies of a single gene, research shows

Published

2 weeks ago

May 7, 2024

Some Alzheimer's cases may be caused by copies of a single gene, research shows

Researchers have identified a genetic form of late-in-life Alzheimer’s disease for the first time, which occurs in people inheriting two copies of the APOE4 gene.
APOE4 is known to increase the risk of Alzheimer’s.
Symptoms in those with two APOE4 copies can manifest seven to ten years earlier compared to those with other risk factors.

For the first time, researchers have identified a genetic form of late-in-life Alzheimer’s disease — in people who inherit two copies of a worrisome gene.

Scientists have long known a gene called APOE4 is one of many things that can increase people’s risk for Alzheimer’s, including simply getting older. The vast majority of Alzheimer’s cases occur after age 65. But research published Monday suggests that for people who carry not one but two copies of the gene, it’s more than a risk factor, it’s an underlying cause of the mind-robbing disease.

The findings mark a distinction with “profound implications,” said Dr. Juan Fortea, who led the study the Sant Pau Research Institute in Barcelona, Spain.

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Among them: Symptoms can begin seven to 10 years sooner than in other older adults who develop Alzheimer’s.

For the first time, researchers have identified a genetic form of late-in-life Alzheimer’s disease — in people who inherit two copies of a worrisome gene. (AP Photo/David Duprey, File)

An estimated 15% of Alzheimer’s patients carry two copies of APOE4, meaning those cases “can be tracked back to a cause and the cause is in the genes,” Fortea said. Until now, genetic forms of Alzheimer’s were thought to be only types that strike at much younger ages and account for less than 1% of all cases.

Scientists say the research makes it critical to develop treatments that target the APOE4 gene. Some doctors won’t offer the only drug that has been shown to modestly slow the disease, Leqembi, to people with the gene pair because they’re especially prone to a dangerous side effect, said Dr. Reisa Sperling, a study coauthor at Harvard-affiliated Brigham and Women’s Hospital in Boston.

Sperling hunts ways to prevent or at least delay Alzheimer’s and “this data for me says wow, what an important group to be able to go after before they become symptomatic.”

But the news doesn’t mean people should race for a gene test. “It’s important not to scare everyone who has a family history” of Alzheimer’s because this gene duo isn’t behind most cases, she told The Associated Press.

HOW DO GENETICS AFFECT ALZHEIMER’S?

More than 6 million Americans, and millions more worldwide, have Alzheimer’s. A handful of genes are known to cause rare “early-onset” forms, mutations passed through families that trigger symptoms unusually young, by age 50. Some cases also are linked to Down syndrome.

But Alzheimer’s most commonly strikes after 65, especially in the late 70s to 80s, and the APOE gene – which also affects how the body handles fats — was long known to play some role. There are three main varieties. Most people carry the APOE3 variant that appears to neither increase nor decrease Alzheimer’s risk. Some carry APOE2, which provides some protection against Alzheimer’s.

APOE4 has long been labeled the biggest genetic risk factor for late-in-life Alzheimer’s, with two copies risker than one. About 2% of the global population is estimated to have inherited a copy from each parent.

RESEARCH POINTS TO A CAUSE FOR A SUBSET OF ALZHEIMER’S

To better understand the gene’s role, Fortea’s team used data from 3,297 brains donated for research and from over 10,000 people in U.S. and European Alzheimer’s studies. They examined symptoms and early hallmarks of Alzheimer’s such as sticky amyloid in the brain.

People with two APOE4 copies were accumulating more amyloid at age 55 than those with just one copy or the “neutral” APOE3 gene variety, they reported in the journal Nature Medicine. By age 65, brain scans showed significant plaque buildup in nearly three-quarters of those double carriers – who also were more likely to have initial Alzheimer’s symptoms around that age rather than in the 70s or 80s.

Fortea said the disease’s underlying biology was remarkably similar to young inherited types.

It appears more like “a familial form of Alzheimer’s,” said Dr. Eliezer Masliah of the National Institute on Aging. “It is not just a risk factor.”

Importantly, not everyone with two APOE4 genes develops Alzheimer’s symptoms and researchers need to learn why, Sperling cautioned.

“It’s not quite destiny,” she said.

HOW THE NEW FINDINGS MAY AFFECT ALZHEIMER’S RESEARCH AND TREATMENT

The drug Leqembi works by clearing away some sticky amyloid but Sperling said it’s not clear if carriers of two APOE4 genes benefit because they have such a high risk of a side effect from the drug – dangerous brain swelling and bleeding. One research question is whether they’d do better starting such drugs sooner than other people.

Masliah said other research aims to develop gene therapy or drugs to specifically target APOE4. He said it’s also crucial to understand APOE4’s effects in diverse populations since it’s been studied mostly in white people of European ancestry.

As for gene tests, for now they’re typically used only to evaluate if someone’s a candidate for Leqembi or for people enrolling in Alzheimer’s research – especially studies of possible ways to prevent the disease. Sperling said the people most likely to carry two APOE4 genes had parents who both got Alzheimer’s relatively early, in their 60s rather than 80s.

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Could your car make you sick? Study highlights potentially cancerous toxins in vehicles

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1 day ago

May 18, 2024

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Could your car make you sick? Study highlights potentially cancerous toxins in vehicles

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Americans may be breathing in cancer-causing chemicals while driving, recent research suggests.

A study published in the journal Environmental Science & Technology has sparked discussions about the potentially harmful toxins that could be lurking in the cabins of vehicles.

“Certainly the indoor air quality can cause health symptoms,” Dr. Ken Speath, M.D., the division chief and medical director for occupational and environmental medicine at Northwell Health on Long Island, New York, told Fox News Digital.

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It is important to be mindful of what you’re breathing in at home, at the office, at school and even in cars, according to Speath, who was not involved in the study.

“There can be situations where levels of harmful chemicals get high enough to potentially cause health harms,” he said.

Americans may be breathing in cancer-causing chemicals while they are driving, recent research suggests. A study published in the journal Environmental Science & Technology has sparked many discussions. (iStock)

“A car is a closed small space — so whatever is in the air is certainly going to be breathed in.”

Research reveals ‘harmful chemicals’

The peer-reviewed study looked at 101 owned vehicles in the U.S., model year 2015 or newer.

The researchers concluded that harmful flame-retardant chemicals — including those suspected of potentially causing cancer and some neurological issues — may be polluting the air inside vehicles.

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“Flame retardant chemicals, which are intentionally added to vehicle interiors to meet flammability standards, are released into the cabin air from the materials to which they were applied,” lead author Rebecca Hoehn, a scientist at Duke University, told Fox News Digital.

“People in these vehicles may be exposed to these chemicals.”

Seat foam was the only material the researchers measured, Hoehn said, but other interior materials could also contain the chemicals.

The researchers concluded that harmful flame-retardant chemicals — including those suspected of potentially causing cancer and some neurological issues — may be polluting the air inside vehicles. (iStock)

“Considering the average driver spends about an hour in the car every day, this is a significant public health issue,” Hoehn warned.

“It’s particularly concerning for drivers with longer commutes, as well as child passengers, who breathe more air pound for pound than adults.”

The chemicals detected in the car cabins included a flame retardant called tris (1-chloro-isopropyl) phosphate (TCIPP), which is currently being investigated as a potential carcinogen by the U.S. National Toxicology Program.

“Considering the average driver spends about an hour in the car every day, this is a significant public health issue.”

Other flame retardants — tris (1, 3-dichloro-2-propyl) phosphate (TDCIPP) and tris (2-chloroethyl) phosphate (TCEP) — were also detected.

These are “two Californian Proposition 65 carcinogens linked to neurological and reproductive harms,” according to a press release.

Higher concentrations of the flame retardants were found during warmer weather.

“We found that the same cars, sampled in both winter and summer, had higher concentrations of flame retardants in the cabin air during the warm summer months,” Hoehn told Fox News Digital.

Flame retardants are added to vehicles to meet the National Highway Traffic Safety Administration Federal Motor Vehicle Safety Standard, which mandated their use in the 1970s. (iStock)

Flame retardants are added to vehicles to meet the National Highway Traffic Safety Administration Federal Motor Vehicle Safety Standard (FMVSS 302), which mandated their use in the 1970s, the release stated.

Flame retardants have been the “focus of concern for some time,” Speath told Fox News Digital.

More information is needed to determine the health risks these chemicals pose in humans, he said.

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“A number of these have been demonstrated in studies to have health harms in animals,” he said.

“That doesn’t necessarily mean that would be true for humans, but it raises that possibility, so we need to study these chemicals more in relation to their effects on humans.”

Higher concentrations of the flame retardants were found during warmer weather, the researchers said. (iStock)

Emanuela Taioli, M.D., PhD, the director of the Institute for Translational Epidemiology at Icahn School of Medicine at Mount Sinai in New York City, was also not part of the study, but shared her reactions.

“This is a very relevant finding, since it may prompt changes in cars’ upholstery, as well as in other parts of the car where there is foam,” she told Fox News Digital via email.

“We also want to know more about this finding and monitor whether it is replicated by other investigators.”

Other sources of toxins

Stephen Showalter, a home inspector and indoor environmental air consultant with Showalter Property Consultants in Maryland, said he typically interviews clients about their history of illness, then tests for potential sources of sickness in buildings, cars, RVs and boats.

Mold is a common culprit when it comes to health issues triggered by one’s environment, he said in an interview with Fox News Digital.

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Dr. Daniel Johns, a member of the International Society of Environmentally Acquired Illnesses and a chiropractor who practices in Annapolis, Maryland, echoed Showalter’s concerns about mold-related health issues.

Johns also cautioned that cars can be a daily source of mold exposure.

“Any water that leaks from a window, sunroof or convertible can get into the carpet and cause mold growth,” he said during an interview with Fox News Digital.

Mold is a common culprit when it comes to health issues triggered by one’s environment, according to an environmental expert. (iStock)

“Mold can start growing on a wet surface within 24 to 48 hours.”

For families with small children, spilled sippy cups could play a role when it comes to mold in cars, Johns warned.

“The water seeps into the upholstery and doesn’t get noticed or properly dried out, and the whole seat can become moldy,” he said.

“Mold can start growing on a wet surface within 24 to 48 hours.”

“Every time you sit on the seat, it releases a mold spore cloud into the car. Once that happens, you can’t clean it away. The upholstery must be removed and replaced.”

The impact of these potentially harmful pollutants can vary from one person to the next, experts told Fox News Digital.

For families with small children, spilled sippy cups could play a role when it comes to mold in cars, an expert warned. (Kids and Car Safety)

People metabolize chemicals and toxins in different ways, according to Taioli.

“Metabolism happens through enzymes that the body produces,” he said.

“Each of us has a different genetic profile that defines our metabolic capacity. As a consequence, the same amount of toxin may be metabolized better/faster by some, and worse/slower by others.”

Tips for ensuring safe interiors

While further research on car-borne chemicals is needed, experts say people can take measures to limit exposure.

“People may be able to reduce their exposure by ventilating their cars,” Hoehn advised.

“For example, rolling down the windows to let out contaminated air, or pulling in fresh air with climate control systems, should reduce concentrations.

“Ultimately, reducing the amount of flame retardants added to vehicles in the first place would provide the greatest reduction in exposure risk.”

Controlling your vehicle’s cabin temperature may also reduce exposure, she added.

“Parking in a garage or shade instead of full sun may reduce the cabin temperature and limit the extent of flame retardant release,” Hoehn said.

The researchers also called for action from regulatory agencies and vehicle manufacturers.

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“Ultimately, reducing the amount of flame retardants added to vehicles in the first place would provide the greatest reduction in exposure risk,” Hoehn noted.

“If flammability standards for vehicles could be revised to meet fire safety guidelines without the use of added flame retardants, risk of flame retardant exposure from personal vehicles could be greatly reduced.”

To prevent mold in a vehicle, experts recommend keeping your windows up when it rains or snows to prevent water from permeating the carpet or fabric. (iStock)

Having your car’s air quality and surfaces tested is one way to reduce the risk of exposure to allergens, toxins and chemicals, experts told Fox News Digital.

To prevent mold in a vehicle, Showalter recommends keeping your windows up when it rains or snows to prevent water from permeating the carpet or fabric.

He also cautioned about leaky air conditioners, which can foster mold growth in vehicles, and about leaving wet items in the car.

Lastly, before buying a used car, he said it is important to check the vehicle’s history to make sure it doesn’t have flood damage, which can lead to mold and other issues.

If you think you are experiencing illness due to chemical exposure in your car, home or office, it’s best to see a health care professional to discuss your symptoms.

Fox News Digital reached out to several major car companies for comment.

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