People with Down syndrome are living longer than ever before. That’s genuinely worth celebrating — it reflects decades of improved medical care, greater inclusion, and better quality of life. But longer lives have also brought new challenges into focus, and one of the most significant is a substantially increased risk of developing Alzheimer’s disease.
This post is primarily for families and professionals supporting people with Down syndrome, though anyone wanting to understand this area of dementia research will find it relevant.
Why is the risk higher?
The connection is genetic. Down syndrome is caused by an extra copy of chromosome 21, which carries the gene responsible for producing amyloid precursor protein (APP). This protein can break down into beta-amyloid — the same substance that forms the plaques found in Alzheimer’s disease. Because people with Down syndrome produce more APP, beta-amyloid accumulates in the brain at a higher rate and from an earlier age.
By their 40s or 50s, most people with Down syndrome show brain changes associated with Alzheimer’s, and many will go on to develop dementia. Other factors, including oxidative stress and inflammation, also contribute to the elevated risk.
How does Alzheimer’s present in people with Down syndrome?
The symptoms overlap with typical Alzheimer’s, but there are differences worth knowing. Memory loss and difficulty retaining new information are common, as are changes in behaviour — increased agitation, withdrawal, or low mood. Decline in everyday skills such as dressing or eating may be noticeable, and seizures can occur in later stages.
One of the challenges is that some of these changes can be mistaken for other health conditions common in people with Down syndrome, such as thyroid problems or sleep apnoea, or simply attributed to ageing. This is why early and accurate diagnosis matters so much — not to cause alarm, but to ensure the right support is in place at the right time.
The importance of early detection
For families and support workers, the most useful thing is to know the person well enough to notice when something has changed. Behavioural shifts, a loss of skills that were previously established, or changes in mood that feel out of character are all worth taking seriously and raising with a GP.
Regular health checks and cognitive assessments should be part of the care plan for anyone with Down syndrome from their 40s onwards. Early diagnosis opens up access to support services, allows time for planning, and means the person themselves can be involved in decisions about their care while they still have capacity to do so.
Supporting someone with Down syndrome and Alzheimer’s
Familiar environments and consistent daily routines make a significant difference — reducing the cognitive load and the anxiety that comes with uncertainty. Meaningful activities, particularly those connected to the person’s existing interests and abilities, help maintain both wellbeing and a sense of identity.
It’s also important to monitor and manage other health conditions that can worsen dementia symptoms — hearing or vision problems, for example, are easily overlooked but have a real impact on how someone experiences the world around them. Emotional support from people the person knows and trusts is equally important, particularly as changes become more pronounced.
Families and carers often benefit from connecting with others in similar situations. Support groups — both for Down syndrome and for dementia — can offer practical advice, reduce isolation, and provide a space to process what can be a complex and emotionally demanding experience.
Looking ahead
Research into the Down syndrome and Alzheimer’s connection is growing. Scientists are exploring therapies that target amyloid plaques, alongside better diagnostic tools that can identify changes earlier. This is a field that has historically been under-resourced, and increased awareness — including among care professionals — is part of what drives progress.
In the meantime, good care, proactive planning, and genuine inclusion make a meaningful difference to people’s lives right now.
Further reading
- Down syndrome and dementia — Alzheimer’s Society (UK)
- Down syndrome and Alzheimer’s — Down’s Syndrome Association (UK)
- Down Syndrome and Alzheimer’s Disease — Alzheimer’s Association
If you support someone with Down syndrome professionally and want to deepen your understanding of dementia, my training covers the full range of dementia types and how they present differently in different people.