💜 Pioneers of Hope: How People With Down Syndrome Are Leading the Way in Alzheimer’s Research

By Melissa J. Long, CTRS | October 15, 2025

When we think of pioneers in medical research, we often imagine white-coated scientists in labs. But some of today’s most important contributors to Alzheimer’s research aren't scientists—they're individuals with Down syndrome and their families.

Why Down Syndrome Is Key to Unlocking Alzheimer’s

Down syndrome, a genetic condition caused by an extra copy of chromosome 21, is best known for its association with intellectual disability. But few people realize that this same extra chromosome also holds a vital clue in understanding Alzheimer’s disease.

On chromosome 21 lies the amyloid precursor protein (APP) gene, which is involved in producing amyloid beta—the sticky protein that forms plaques in the brains of people with Alzheimer’s. Because individuals with Down syndrome have an extra copy of this gene, their brains produce more amyloid, putting them at an exceptionally high risk for developing Alzheimer’s disease.

In fact, by age 40, virtually all individuals with Down syndrome show the biological signs of Alzheimer’s in their brains—even if they don’t show outward symptoms yet. And as medical care improves, more individuals with Down syndrome are living into their 60s, making it increasingly likely they will face Alzheimer’s-related cognitive decline.

This unique combination makes people with Down syndrome a crucial population for Alzheimer’s research, especially for testing early interventions that aim to prevent or slow the disease.

Real People, Real Impact

Take Justin McCowan, for example. At age 39, Justin traveled over 100 miles with his parents to participate in an experimental Alzheimer’s drug trial at the University of California, San Diego (UCSD). He underwent MRIs, memory testing, and hours of blood draws—all in hopes of helping scientists learn more about the disease.

Why did he volunteer? To help others. Especially a friend named Maria, who also has Down syndrome and is experiencing memory loss. “I feel very sad about Maria because she doesn’t remember anything,” Justin said.

Stories like Justin’s remind us that people with Down syndrome aren’t just research subjects—they’re active partners in the search for a cure.

How This Research Helps Everyone

What researchers learn from people with Down syndrome could benefit millions of people without the condition. According to Dr. William Mobley, Chair of Neurosciences at UCSD, this is the only population in the world where scientists can predict with near certainty who will get Alzheimer’s. That predictability allows researchers to test preventive treatments long before symptoms appear—something that’s incredibly hard to do in the general population.

Imagine a future where all of us could start taking a simple medication in our 20s or 30s to prevent Alzheimer’s before it starts. That’s the dream researchers are chasing—thanks in part to the contributions of people with Down syndrome.

Signs of Cognitive Decline: What Caregivers Should Watch For

Caregivers of individuals with Down syndrome should be aware of the signs of Alzheimer’s-related decline, which can be different from typical aging. Look for:

• Increased forgetfulness or confusion

• Changes in personality or behavior

• Difficulty with language or communication

• Challenges with everyday tasks they used to do well

• Withdrawal from favorite activities or social interactions

A poignant example shared by researchers is a series of signatures from a woman named Irma, who had Down syndrome. Her elegant script slowly deteriorated over a decade—eventually fading to almost nothing. It’s a visual reminder of what Alzheimer’s does, and why early detection and treatment matter so much.

Looking Ahead: From Research to Reality

Today, researchers continue to test promising new therapies, including eye exams that could one day screen for Alzheimer’s in a simple, non-invasive way. Experimental drugs that worked in mice are now being tested in people with Down syndrome, in the hopes that they’ll prevent the disease from ever taking hold.

There’s still a long way to go—but people like Justin are leading the way. As his mother, Annamarie, shared, “We hope that what scientists are learning from people like Justin will help keep his memory—and others'—intact.”

Final Thoughts for Caregivers

If you’re caring for someone with Down syndrome, know this: your loved one is part of something much bigger. Their life, their health, and even their challenges are helping scientists get closer to solving one of the biggest medical mysteries of our time.

You are not alone—and the work you're doing is part of a larger story of hope, resilience, and scientific discovery.

Resources for Caregivers:

• National Down Syndrome Society (NDSS)

• Alzheimer's Association – Down Syndrome & Alzheimer’s

• Global Down Syndrome Foundation – Alzheimer’s Research

• Alzheimer's Society - Down syndrome and Alzheimer’s disease

• ABC-DS is longitudinal study examining biomarkers of AD in adults with Down syndrome 

• NPR initial article on topic