Alzheimer’s Disease in People with 

Down Syndrome

FACT SHEET

National Institute on Aging

Eunice Kennedy Shriver National Institute of Child 

Health and Human Development

Alzheimer’s and Down 

Syndrome — Get the Facts

■ The Connection between Down

Syndrome and Alzheimer’s Disease

■ Alzheimer’s Disease Symptoms

■ Down Syndrome and Alzheimer’s

Research

■ Participating in Research

■ For More Information

People with Down syndrome are living 

longer than ever before. Getting older 

can bring new health challenges, 

including Alzheimer’s disease. 

The Connection between 

Down Syndrome and 

Alzheimer’s Disease

Many, but not all, people with Down 

syndrome develop Alzheimer’s disease 

when they get older. Alzheimer’s is an 

irreversible, progressive brain disorder 

that slowly destroys memory and 

thinking skills and, eventually, the 

ability to carry out simple tasks. 

Alzheimer’s disease is the most common 

cause of dementia among older adults. 

Dementia is the loss of cognitive 

functioning—thinking, remembering, 

and reasoning—and behavioral abilities 

to such an extent that it interferes with 

a person’s daily life and activities.

People with Down syndrome are born 

with an extra copy of chromosome 21, 

which carries the APP gene. This gene 

produces a specific protein called amyloid 

precursor protein (APP). Too much APP 

protein leads to a buildup of protein 

clumps called beta-amyloid plaques in 

the brain. By age 40, almost all 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 dementia.

However, not all people with these brain 

plaques will develop the symptoms of 

Alzheimer’s. Estimates suggest that 50 

percent or more of people with Down 

syndrome will develop dementia due to 

Alzheimer’s disease as they age.

Alzheimer’s Disease 

Symptoms

Many people with Down syndrome begin 

to show symptoms of Alzheimer’s disease 

in their 50s or 60s. But, like in all people 

with Alzheimer’s, changes in the brain 

that lead to these symptoms are thought 

to begin at least 10 years earlier. These 

brain changes include the buildup of 

plaques and tangles, the loss of 
2

2

connections between nerve cells, the death 

of nerve cells, and the shrinking of brain 

tissue (called atrophy). 

The risk for Alzheimer’s disease increases 

with age, so it’s important to watch for 

certain changes in behavior, such as: 

■ increased confusion 

■ short-term memory problems (for 

example, asking the same questions 

over and over)

■ reduction in or loss of ability to do 

everyday activities 

Other possible symptoms of Alzheimer’s 

dementia are:

■ seizures that begin in adulthood

■ problems with coordination and 

walking

■ reduced ability to pay attention 

■ behavior and personality changes, such 

as wandering and being less social

■ decreased fine motor control

■ difficulty finding one’s way around 

familiar areas 

If you notice any of these changes, see a 

healthcare provider to find out more. 

Keep in mind, though, that not all 

dementia symptoms are caused by 

Alzheimer’s disease. Other conditions, 

such as medication side effects, depression, and kidney, thyroid, and liver 

problems, can also cause dementia 

symptoms. Some of these conditions can 

be treated and reversed. 

Currently, Alzheimer’s disease has no 

cure, and no medications have been 

approved to treat Alzheimer’s in people 

with Down syndrome. 

Down Syndrome and 

Alzheimer’s Research

Alzheimer’s can last several years, and 

symptoms usually get worse over time. 

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. 

Research in this area includes:

■ basic studies to improve our 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. Clinical trials are the best 

way to find out if a treatment is safe 

and effective in people. 

Participating in Research

New treatments, tests, and other discoveries 

would not be possible without volunteers 

who participate in clinical studies and trials. 

By volunteering, people can help others, 

receive care from medical providers, and 

possibly test new treatments.

Volunteers and their caregivers should 

consider a study’s risks as well as its 

benefits. For example, a new drug being 
3

tested may have potential side effects. 

Researchers must follow federal and 

international rules to ensure that all 

participants are safe and that their 

personal information remains confidential. 

Study staff can explain safety and other 

issues and answer questions as you decide 

whether to participate in a research study 

or clinical trial. 

But not everyone can participate in a 

clinical trial. Studies have specific 

requirements that people must meet to 

participate. For example, participants 

must be of a certain age, have a certain 

diagnosis, or have a specific genetic makeup. 

These requirements help ensure that the 

results of a study are reliable and useful.

Family members and other caregivers play 

an important role for adults with Down 

syndrome who participate in clinical 

research. They may be asked to provide 

consent or permission for the person with 

Down syndrome to take part in the study, 

accompany the person to study visits, and 

answer health questions about him or her. 

“Informed consent” is a process in which 

researchers explain the study in detail, 

describe all the possible risks and benefits 

of the study, and clarify participants’ rights. 

Those who decide to participate sign a 

written agreement stating that they 

understand the risks and benefits and 

agree to participate in the study. If a 

person cannot provide this consent, a 

legally authorized representative, such as a 

family member or caregiver, may give 

permission. The person with Down 

syndrome would also need to agree, called 

assent, to be in the study.

There are many ways to learn about research opportunities

■ Join DS-Connect®, a voluntary, confidential, online registry from the Eunice 

Kennedy Shriver National Institute of Child Health and Human Development 

(part of the National Institutes of Health, or NIH). You, your legally authorized 

representative, or your guardian can submit information about your health and 

choose to be contacted about research opportunities, if desired. Visit 

https://dsconnect.nih.gov or email DSConnect@nih.gov for more information 

and to sign up. 

■ Search the National Institute on Aging’s Alzheimer’s disease clinical trials finder, 

www.nia.nih.gov/alzheimers/clinical-trials. 

■ Look at the National Down Syndrome Society’s directory of studies, 

www.ndss.org/resources/current-research. 

■ Visit NIH’s “Clinical Research Trials and You,” www.nih.gov/health-information/

nih-clinical-research-trials-you.
4

4

For More Information

Alzheimer’s and related Dementias 

Education and Referral (ADEAR) 

Center

1-800-438-4380 (toll-free)

adear@nia.nih.gov

www.alzheimers.gov

The National Institute on Aging’s ADEAR 

Center offers information and publications 

for families, caregivers, and professionals on 

diagnosis, treatment, patient care, 

caregiver needs, long-term care, education, 

training, and research related to 

Alzheimer’s disease. Staff members 

answer telephone, email, and written 

requests and make referrals to local and 

national resources. Visit the ADEAR 

website to learn more about Alzheimer’s 

and other dementias, find clinical trials, 

and sign up for email updates.

Down Syndrome and Alzheimer’s 

Disease

Alzheimer’s Disease & Down 

Syndrome

www.ndss.org/resources/alzheimers

Down Syndrome and Alzheimer’s 

Disease

www.alz.org/alzheimers-dementia/what-isdementia/types-of-dementia/down-syndrome

Aging and Down Syndrome: A Health 

& Well-Being Guidebook

www.ndss.org/wp-content/uploads/2017/11/

Aging-and-Down-Syndrome.pdf

Down Syndrome Research and 

Resources

Down Syndrome Consortium

https://downsyndrome.nih.gov

Down Syndrome: Overview

www.nichd.nih.gov/health/topics/down 

syndrome

DS-Connect®: The Down Syndrome 

Registry

https://dsconnect.nih.gov

LuMind Research Down Syndrome 

Foundation

www.lumindrds.org

Other Alzheimer’s Resources

Alzheimer’s Association

www.alz.org

Alzheimer’s Foundation of America

www.alzfdn.org

National Institute on Aging

Eunice Kennedy Shriver National Institute of Child 

Health and Human Development

National Institutes of Health

NIH...Turning Discovery Into Health®

U.S. Department of Health and Human Services

NIH Publication No. 16-AG-8021 January 2016