The average age of diagnosis of Alzheimer's disease in people with Down syndrome is around 53-56 years of age (the age varies from study to study). The development of symptoms of Alzheimer's disease before the age of 40 is uncommon. However, the changes in the brain that contribute to Alzheimer's disease tend to occur much earlier (likely years before developing symptoms).
In this webinar recording, Brian Chicoine, MD, provides information on Alzheimer's disease prevention and healthy aging in people with Down syndrome.  

Our Resource Library has additional articles and webinars about Alzheimer’s disease in people with Down syndrome in the Alzheimer's Disease and Dementia section.