My dad’s sister Penny had limited speech. Most people couldn’t understand much of what she said. But there was one phrase she had down cold — one phrase that was perfectly clear every single time.
“I know you.”
It didn’t matter if she’d just met you or known you for decades. Penny greeted everyone the same way, with that phrase and whatever came with it — the smile, the recognition, the warmth. In three words, she made people feel seen.
Then Alzheimer’s came. And it took exactly that.
What Families with Down Syndrome Need to Know
June is Alzheimer’s & Brain Awareness Month, and if your sibling has Down syndrome, this is a conversation you need to have — even if they’re young, even if they seem fine, even if no one in your family has brought it up yet.
Here’s the reality: Down syndrome and Alzheimer’s disease are biologically linked in a way that sets this population apart from everyone else. People with Down syndrome carry an extra copy of chromosome 21, which also carries the APP gene — the gene responsible for producing amyloid protein. That means amyloid plaques, the hallmark of Alzheimer’s, begin building up in the brains of people with Down syndrome decades before any symptoms appear. By age 40, most people with Down syndrome already have significant plaque and tangle pathology in their brains.
The numbers are staggering. In the general population, about 5% of people ages 65–74 have Alzheimer’s. For people with Down syndrome, the lifetime risk is 95%. Research published in The Lancet Neurology found that approximately 70% are diagnosed with dementia by around age 54. A large Medicare and Medicaid study of over 132,000 adults with Down syndrome found that 23% already had an Alzheimer’s diagnosis — and among those 55 and older, prevalence climbed to 42% and kept rising.
The average age of onset? 54.5 years. Penny was likely under 50.
And if Alzheimer’s runs in your family — as it does for many families who also have a sibling with Down syndrome — research shows your own risk increases significantly too. Having one first-degree relative with Alzheimer’s raises your risk by 73%. Having a parent and an aunt or uncle diagnosed increases it dramatically more.
This isn’t meant to frighten you. It’s meant to inform you — because early detection matters, and families are often the first to notice the signs.
What Does Early Decline Look Like?
This is where it gets complicated for our sibs. Standard Alzheimer’s screening tools aren’t designed for people with intellectual disabilities. Someone with limited language can’t answer the typical memory questionnaire. Someone who never drove a car can’t be assessed for getting lost while driving.
This is exactly why the NTG-Early Detection Screen for Dementia (NTG-EDSD) exists. It was designed specifically for adults with intellectual disabilities — including those with limited or no verbal communication. Instead of asking the individual questions, it guides caregivers and family members to document functional changes over time: sleep patterns, daily living skills, behavior shifts, gait changes, social withdrawal. It creates a baseline so that decline can be tracked and brought to a physician.
It’s recommended starting at age 40 for anyone with Down syndrome — annually, whether or not you’re worried yet.
I’ve made the NTG-EDSD available as a free download exclusively for SpecialSib subscribers. It takes 15–60 minutes to complete and can be filled out by anyone who has known your sibling for six months or more — no clinical background required. Sign up for the SpecialSib email list and get your copy here: https://mailchi.mp/soultosoulyogasrq/ddeziww9zu
What You Can Do Right Now
If your sibling with Down syndrome is approaching or over 40, talk to their physician about Alzheimer’s screening and make sure it’s part of their annual wellness visit. Bring documentation of any changes you’ve noticed — sleep, mood, memory, daily skills. Push for a referral to a neurologist who has experience with this population if you’re concerned.
And if you’ve already walked this road — if you watched your sibling, or an aunt, or a cousin with Down syndrome lose ground to this disease — know that you’re not alone in that grief. It is a particular kind of loss, watching someone’s personality change before their body does. Watching the things that made them them slip away quietly.
Penny greeted everyone with “I know you.” Until she didn’t anymore.
I don’t know exactly when she stopped. But I know what was lost when she did.
Cheryl Albright, OTR/L, C-IAYT
Cheryl is an occupational therapist, yoga therapist, and the founder of SpecialSib.com — a space dedicated to the siblings who often get forgotten in the conversation.
