Is There Personalized Medicine for Alzheimer’s Disease?

Learning which genes you carry could motivate you to take better care of your health and delay or prevent the disease. Here’s what you should know about genetic testing for Alzheimer’s disease.

Sharon and her sister Sandra worry that they may inherit the mutant gene that caused Alzheimer’s disease in their mother. Sharon wants to be tested and find out. Sandra doesn’t.

Nearly seven million Americans are living with Alzheimer's, most of them women over the age of 75. By 2050, the number is projected to rise to nearly 13 million.

To help prevent the disease, scientists hope to develop predictive mathematical models using artificial intelligence that will allow doctors to diagnose the illness earlier based on objective biomarkers rather than symptoms, which can vary greatly from one patient to the next. But that day is still in the future.

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At the moment, your only choice is genetic testing and testing to assess your cognitive function. Usually, Alzheimer’s does not have a single genetic cause, arising instead from a combination of multiple genes and other factors. You can also develop the disease even if you do not have a family history. But as Sharon and Sandra know, you have a higher risk if a parent or sibling is diagnosed with the disease.  

Should you get tested? Your family experience may influence your choice.

“We started noticing signs of the disease in my mother when she was in her late 50s,” Sharon said. “Most people think it’s memory loss. It’s a lot more than that. Yes, she was forgetful, but she was also confused and angry.”

Sharon remembers her mother with a happy-go-lucky disposition. “That was before the onset of the disease,” she said. “I want to have the genetic testing done because I want to see what steps I can take to delay the process — if any. My sister wants no part of knowing. We both witnessed how Alzheimer’s robbed our mother of her personality and her well-being. It’s a cruel disease.”

Their mother had early-onset Alzheimer’s disease, which occurs in people under the age of 65 but represents less than 10 percent of all cases.

Researchers have identified three rare single-gene mutations that cause early-onset Alzheimer’s. The genes can cause abnormal amyloid proteins to form, which accumulate in the brains of people with Alzheimer’s. About half of the children of parents with early-onset Alzheimer’s carry one or more of the gene mutations and have a high probability of developing the disease. 

You’re less likely to inherit late-onset Alzheimer’s from a parent. But if you inherit a particular form of the apolipoprotein E (APOE) gene on chromosome 19, your risk is higher than if you hadn’t. 

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Even if you don’t choose testing, tell your doctor about your family history. Some years ago, the Alzheimer’s Association concluded that physicians revealed the diagnosis to only 45 percent of people with Alzheimer’s or to their caregivers. Your doctor may wish to protect you from devastating news. Studies, however, have explored the issue and found that few patients become depressed or have other long-term emotional problems after hearing about their diagnosis.

Knowing the truth is likely to help you find the best care and participate in decisions about your care, including providing informed consent for current and future treatment plans. It gives you an opportunity to get the maximum benefit from available treatments and possibly participate in ongoing research trials. It may also motivate you to take the trip of a lifetime or write your memoir while you still can.

Most drugs work best for people in the early or middle stages of Alzheimer’s. They include galantamine, rivastigmine, and donepezil, a group called cholinesterase inhibitors. Lecanemab and aducanumab are immunotherapies. The drugs target the protein beta-amyloid to help reduce amyloid plaques, one of the hallmark brain changes in Alzheimer’s.

But it is not clear how helpful the treatments may be. There are no known interventions that cure Alzheimer’s.

Before you need medication, your best chance of delaying the disease is to live a healthy life:

• Quit smoking. Smoking can cause cognitive decline. 
• Stay fit. Being in good physical shape can reduce cognitive decline. 
• Do crossword puzzles. Take classes. Giving your brain a workout can be beneficial.
• Eat a heart-healthy diet.
• Surround yourself with friends. Research shows that feeling lonely can increase cognitive decline.

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