The most common form of dementia causes problems with memory, behavior, and thinking that worsen over time, eventually leading to death. There is no cure. Over 5 million people in the United States have the disease. Alzheimer's is not a normal part of aging.
Alzheimer's and Down Syndrome
Alzheimer's disease occurs three to five times more often among people with Down syndrome than the general population. People with Down syndrome are also more likely to develop Alzheimer's disease at a younger age than other adults.
As with all adults, advancing age also increases the chances that a person with Down syndrome will develop Alzheimer's disease. Estimates vary, but it is reasonable to conclude that 25 percent or more of people with Down syndrome who are older than 35 show clinical signs and symptoms of Alzheimer's-type dementia.
However, it is important to note that not everyone with Down syndrome develops Alzheimer's symptoms.
Is it Alzheimer's Disease?
Down Syndrome and Alzheimer's Disease
Dementia and Intellectual Disabilities (PDF)
WebMD: Down Syndrome and Alzheimer's Disease Risk
My Thinker's Not Working
Administration on Intellectual and Developmental Disabilities