Critter Corner: Is there a Link Between Alzheimer’s and Down Syndrome?

Dear Oakley,

My neighbor has Down Syndrome. I read somewhere that there is a link between Down Syndrome and Alzheimer’s. Is this true and if so, what research is being done?


Khan Nexion

Dear Khan,

Every year, about 6,000 American children are born with Down syndrome (DS), the most common chromosomal alteration. Many don’t realize this, but adults with DS are at a very high risk for developing Alzheimer’s disease (AD).

Here’s why: People with Down syndrome are born with an extra copy of chromosome 21, which carries a gene that produces a specific protein called amyloid precursor protein (APP). Too much APP protein leads to a buildup in the brain of protein clumps called beta-amyloid plaques, the presence of which is one of the hallmarks of Alzheimer’s disease.

By age 40, most people with Down syndrome have these plaques, along with other protein deposits, called tau tangles, which cause problems with how brain cells function and increase the risk of developing Alzheimer’s symptoms. Estimates suggest that 50% or more of people with Down syndrome will develop dementia due to Alzheimer’s disease as they age.

Here’s what we know:

  • Virtually all adults with DS have brain changes consistent with AD by age 40, and a high percentage of them go on to develop dementia by their late 60s.
  • Many but not all people with Down syndrome develop Alzheimer’s disease when they get older.
  • There is wide variation in the age at dementia symptoms start, which suggests there are additional genetic, biological, and environmental factors that influence disease progression.
  • The type of Alzheimer’s in people with Down syndrome is not passed down genetically from a parent to a child.
  • More research is needed to better understand how AD develops in people with DS and to develop possible treatments to delay or prevent it.

The INCLUDE Project and Alzheimer’s research

Scientists are working hard to understand why some people with Down syndrome develop dementia while others do not. They want to know how Alzheimer’s disease begins and progresses so they can develop drugs or other treatments that can stop, delay, or even prevent the disease process. They are also hopeful that research on Alzheimer’s and Down syndrome will not only help those with both conditions, but also may lead to effective treatments for all people with Alzheimer’s. Research in this area includes:

  • Basic studies to improve understanding of the genetic and biological causes of brain abnormalities that lead to Alzheimer’s;
  • Observational research to measure cognitive changes in people over time;
  • Studies of biomarkers (biological signs of disease), brain scans, and other tests that may help diagnose Alzheimer’s — even before symptoms appear — and show brain changes as people with Down syndrome age;
  • Clinical trials to test treatments for dementia in adults with Down syndrome.

In 2018, NIH launched the INCLUDE (INvestigation of Co-occurring conditions across the Lifespan to Understand Down syndromE) project to address health and quality-of-life needs for people with Down syndrome. Through INCLUDE-supported studies, researchers are exploring connections between Down syndrome and other conditions including Alzheimer’s, autism, cataracts, celiac disease, congenital heart disease, and diabetes.

Down Syndrome and Alzheimer’s Disease Resources

For more information about Down Syndrome and Alzheimer’s, visit:


If you have a loved one with Down Syndrome and/or Alzheimer’s, planning ahead is very important. Be sure to contact the Farr Law Firm for a no-cost initial consultation.

Hope this helps!

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About Renee Eder

Renee Eder is the Director of Public Relations for the Farr Law Firm, and gives the voice to the Critters of Critter Corner. Renee’s poodle, Penny, is an official comfort dog who she and her children bring to visit with seniors who are in the early stages of dementia at a local senior home once a month.

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