September 21 is World Alzheimer's Day. One connection is usually overlooked: People with trisomy 21 are more likely to develop Alzheimer's disease, and they tend to do so much earlier. Sandra Loosli, head of neuropsychology at the Department of Neurology, explains why this is the case and why it makes sense to start taking preventive measures as early as age thirty.
Alzheimer’s is considered a disease of old age. That is not true for some people. “People with trisomy 21, or Down syndrome, have a significantly increased risk of developing Alzheimer’s disease,” says Dr. phil. Sandra Loosli, Head of the Department of Neuropsychology at the USZ. The first changes in the brain can be detected as early as age 40, and the diagnosis is often made in a person’s early to mid-50s
An extra copy of a gene as a trigger
The reason lies in genetic predisposition. In trisomy 21, there are three copies of chromosome 21—and the gene for the amyloid precursor protein is located on that very chromosome. “The additional copy of the gene causes more of this protein to be produced, which can lead to increased beta-amyloid buildup in the brain,” explains Loosli. These deposits are a key characteristic of Alzheimer’s disease.
The first signs are often not memory problems
What family members and caregivers often notice first are usually not memory lapses, but changes in behavior or personality: a waning interest in familiar activities, withdrawal, mood swings, reduced drive, or a growing sense of uncertainty in daily life. In addition, there may be difficulties navigating familiar surroundings, increasing forgetfulness, or a greater need for assistance with daily activities.
Taking such signs seriously doesn’t mean assuming the worst. “Not every change in cognitive function is due to dementia,” Loosli emphasizes. Depression, thyroid disorders, sleep disturbances, and hearing or vision impairments can also cause similar symptoms—and are treatable. An early assessment provides clarity and gives those around the person time to prepare, so that independence can be maintained for as long as possible.
Because the baseline cognitive abilities of people with trisomy 21 vary widely, standard tests designed for the general population often fall short in this context. For this reason, the USZ’s Trisomy 21 clinic uses specially adapted testing procedures; the key factor is always a comparison with the individual’s previous level of functioning, for which information from family members is essential.
What Those Around Them Can Do
As a preventive measure, Loosli recommends:
- An active lifestyle: plenty of exercise—such as through programs offered by Insieme 21 or at sports clubs—and a healthy diet
- Mental stimulation: an activity or pursuit that is challenging without being overwhelming
- Stable social relationships: regular social activities and as few changes in primary caregivers as possible
- Regular preventive care: Starting at age 30, checkups are recommended about every five years
Loosli draws confidence from the state of research: People with trisomy 21 are increasingly being included in studies, and new methods—such as blood-based biomarkers—will simplify diagnosis in the future. She hopes that the growing interest among many professionals in the topic of dementia in individuals with intellectual developmental disabilities will, in the medium term, lead to more care options for this patient group.