It was only comparatively recently that people with Down's syndrome were found to be at more at risk of getting Alzheimer's disease. People with Down's syndrome (DS) can begin to show signs of Alzheimer's as young as 40 years of age.
Are the symptoms of Alzheimer's the same for people with Down's Syndrome?
The symptoms of Alzheimer's disease are the same, but they are often missed or misinterpreted. Symptoms include memory loss, weight loss, apathy, personality changes, loss of conversation...

10 Signs of Alzheimer's
10 Ways to Protect Your Brain Against Alzheimer’s
10 Things to Do After an Alzheimer's Diagnosis
Seven Facts You Should Know About Alzheimer's Disease