Genetics

Why Learn Your Genetic Risk for Alzheimer’s Disease?

By Charlotte Huff

Illustration by Cliff Alejandro

Editor’s note: This post originally appeared as a sidebar to a story in the summer/fall 2014 issue of Genome. Go here to read Charlotte Huff’s full report on Alzheimer’s and personalized medicine.

Alzheimer’s disease might provide one of the best opportunities to understand how people cope with unsettling genetic news, says Robert Green, a neurologist and medical geneticist at Harvard Medical School.

“It’s just about the scariest disease that you can think of, and there’s no treatment,” he says. “It’s sort of the worst case scenario for anxiety and stress.”

Green has been involved in a series of studies, part of a research effort dubbed REVEAL (Risk Evaluation and Education for Alzheimer’s Disease), looking at the psychological and practical ripple effects of testing positive for APOE4, a risk factor for late-onset Alzheimer’s. It turns out that the participants, who have a parent with the disease but no symptoms themselves, handle a positive finding relatively well. “They are unhappy,” Green says. “But they do not have catastrophic reactions.”

In fact, they don’t experience any greater anxiety or depression than those participants who aren’t provided their results, according to a New England Journal of Medicine study published in 2009 that involved 162 adults. The only participants who seem more emotionally vulnerable, Green says, are those prone to anxiety in the first place.

Despite the lack of treatment options at this point, some people find the information useful, Green says. Even if they test positive, they frequently overestimate their risk, and their fears can be eased to some degree, he says. Some participants adopt a practical mindset. The percentage with long-term-care insurance increased from 19.8 percent to 27 percent one year after learning their APOE profile. Roughly three-fourths of that jump involved a positive APOE4 result, researchers said.

Gloria VanAlstine already had long-term-care insurance when she decided to participate in REVEAL. Her blood work showed that one of the two APOE genes that she had inherited, one from each parent, was APOE4. (Her mother developed symptoms in her early 70s.) Her risk was described as moderately elevated, with a 54 percent chance of developing the disease during her lifetime.

If VanAlstine had carried two copies of APOE4, her risk would have been higher. Individual risk also depends on age, race, family history, and other factors. For those without any family history, the lifetime Alzheimer’s risk is 10 to 15 percent.

VanAlstine doesn’t fret over occasional memory hiccups. “Of course, I don’t want to get it,” says the 63-year-old retired nurse. “But then I don’t want to get hit by a car, I don’t want to get a heart attack, and all of those other things.”

Robin McIntyre, whose mother developed a rare, early-onset form of the disease in her 40s, knows that her own genetic answers are “sitting in an envelope,” results from when her blood was drawn several years ago for research purposes. Since her mother is a genetic carrier, the 31-year-old faces a 50 percent chance of testing positive, essentially guaranteeing that she’d eventually develop the symptoms.

Still, McIntyre sees value in one day knowing rather than guessing. “I would rather be proactive rather than just be oblivious to what might be happening to me,” she says. The information might influence whether or how she starts a family. Hopefully, it will provide immeasurable peace, she says.

“I wouldn’t have to be second-guessing myself all of the time. There are times where I’m forgetful and I think, ‘Oh, my God. Is my brain changing already? Is the Alzheimer’s starting now?’”