What to Know About Younger-Onset Alzheimer’s Disease

a puzzle of a brain with a piece missing

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The condition often gets misdiagnosed. 

Alzheimer’s disease has been traditionally thought of as an “old person’s disease,” but that’s not always the case. Many people aren’t aware that the brain disease, which slowly destroys memory and other mental functions, can start manifesting before age 60 — and even decades earlier.

In what’s known as early-onset (or younger-onset) Alzheimer’s disease, toxic changes in the brain can start well before any symptoms appear. It’s not until a naturally occurring protein in and around the brain starts to build up at an abnormally high level that people start to notice disruptions to their daily lives. 

“This is an active area of study, but we do know that the amyloid protein begins accumulating indiscriminately throughout the brain decades before any symptoms arise,” explains Mayo Clinic neurologist, Dr. David T. Jones, who specializes in early-onset Alzheimer’s. 

But before you panic, there are some steps you can take to prevent this condition — and learn more about how you might be at risk. 

What is early-onset Alzheimer’s disease?

Alzheimer’s disease is a neurologic disorder that causes the brain to slowly shrink and cells to die. Though it typically first appears in people in their mid-60s, early-onset Alzheimer’s typically affects people in their 40s or 50s, or in some cases, as early as their 30s. 

Given the variability from person-to-person and the general lack of research about early-onset Alzheimer’s, Dr. Jones says it’s hard to predict how long someone will live after an initial diagnosis  — it ranges anywhere from a few years to 20 years. But the good news is that early-onset is relatively uncommon and represents less than 10 percent of all Alzheimer’s cases, according to the National Institute on Aging

What causes early-onset Alzheimer’s?

While the exact causes of early Alzheimer’s disease aren’t fully understood yet, scientists believe it’s caused by the abnormal build-up of two proteins in the brain known as amyloid and tau. At a basic level, the failure of these proteins to function properly disrupts brain cells and leads to damage to the neurons, causing them to eventually die. 

Though rare, it could also run in the family due to a faulty gene. Known as “familial Alzheimer’s disease,” early-onset typically affects members of the same family in every generation, but this occurrence typically accounts for 1 percent or less of cases, according to the Alzheimer’s Association. 

Still, there might not be any one cause of early Alzheimer’s disease: health, environment, and lifestyle may all be contributing factors. For instance, researchers found a possible link between vascular conditions like heart disease and Alzheimer’s, according to a 2017 study from the Journal of the American Medical Association.

What are the most common early symptoms of Alzheimer’s?

Though there are only two types of Alzheimer’s, their symptoms couldn’t be more different. Early-onset Alzheimer’s disease leads to more functional, visual, and language impairments than memory problems. Dr. Jones says people with early-onset symptoms will sometimes go to the eye doctor thinking they have a vision issue, when the real issue is with their brain. 

“Typically, Alzheimer’s will begin with memory problems, which appear as benign forgetfulness, and then that progresses to something more significant, such as getting lost while driving, forgetting where you placed items, and repeating questions,” Dr. Jones tells KCM. “But with younger-onset Alzheimer’s, people have visual dysfunction, like being unable to read, follow the lines in a book, or find things in a junk drawer.” 

Other common symptoms include trouble finding words or repeating sentences, asking for the same information repeatedly, and having a hard time solving basic problems, such as keeping track of bills or following directions. 

How is early-onset Alzheimer’s disease usually diagnosed? 

What makes younger-onset Alzheimer’s difficult to diagnose, according to Dr. Jones, is that it often gets mistaken for psychiatric diseases, other forms of dementia, alcohol and drug abuse, or certain vitamin deficiencies. 

“Patients often struggle for years with not getting a proper diagnosis, especially when it happens earlier in life, because primary care providers and other practitioners are not really expecting or looking for Alzheimer’s in these age groups,” he says. 

This is why doctors opt for a slightly different approach when trying to make a diagnosis, such as using biological markers of the disease process and then measuring spinal fluid for Alzheimer’s proteins. Other methods include molecular brain imaging or Amyloid PET scans to visualize any toxic proteins in the brain. Scientists are also looking into whether blood tests might help identify proteins associated with Alzheimer’s, but Dr. Jones says more research is needed on this method. 

How can you prevent early-onset Alzheimer’s disease? 

As the exact cause of Alzheimer’s is still unknown, there’s no surefire way to prevent the condition. But Dr. Jones says healthy lifestyle choices, like eating a nutritious diet and staying active, benefit your brain, just as they do your heart or any other organ in your body.

“Everything a cardiologist has ever told you about ways to keep your heart healthy is also true for the brain, because the brain has blood vessels, which need to stay healthy. And that means a nutritious diet, exercise, and a good night’s sleep,” he says. 

Social interaction is also key for your overall brain health, which Dr. Jones admits is challenging right now, since the coronavirus continues to take on new variants. But he recommends keeping up with friends and family or just staying active in your community as much as possible.

“If we could bottle up all these lifestyle habits into a pill for prevention, that would be highly effective,” says Dr. Jones. 

On top of lifestyle changes, the Food & Drug Administration just granted accelerated approval for the first Alzheimer’s drug in 18 years this past June. Aducanumab, also known as Aduhelm, is shown to improve mild to moderate Alzheimer’s by removing the buildup of amyloid in the brain.

“As we have learned from the fight against cancer, the accelerated approval pathway can bring therapies to patients faster while spurring more research and innovation,” said Patrizia Cavazzoni, M.D., director of the FDA’s Center for Drug Evaluation and Research.