Alzheimer’s Disease

in People With Down 

Syndrome 

People with Down syndrome are living 

longer than ever before. Yet growing 

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 — the 

most common cause of dementia — 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. Estimates suggest that 50% or more 

of people with Down syndrome will develop 

dementia due to Alzheimer’s as they age. 

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 of protein clumps called betaamyloid plaques in the brain. The presence 

of beta-amyloid plaques is one of the 

hallmarks of Alzheimer’s. 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 this disease. However, 

not all people with these brain plaques will 

develop the symptoms of Alzheimer’s.

ALZHEIMER’S AND RELATED DEMENTIAS EDUCATION AND REFERRAL CENTER Get more facts at nia.nih.gov 1

Learn 

About

FACT SHEET

• The Connection Between 

Down Syndrome and 

Alzheimer’s Disease

• Alzheimer’s Disease 

Symptoms

• Down Syndrome and 

Alzheimer’s Research

• Participating in Research

• Finding More Resources
Alzheimer’s Disease 

Symptoms 

People with Down syndrome can begin 

to show symptoms of Alzheimer’s in their 

40s. But, like in all people with Alzheimer’s, 

changes in the brains of people with Down 

syndrome 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 

connections between nerve cells, the death 

of nerve cells, and the shrinking of brain 

tissue (called atrophy). 

The risk for Alzheimer’s disease in people 

with Down syndrome 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 in people with Down syndrome are: 

• Problems with coordination and walking 

• Reduced ability to pay attention 

• Behavior and personality changes, such 

as restlessness and being less social 

• Changes in sleep 

• Decreased fine motor control 

• Difficulty finding one’s way around 

familiar areas 

Changes in behavior and function may 

vary based on a person’s abilities before 

symptoms of dementia were apparent. 

Still, if you notice any of the changes listed 

above, contact a health care provider to 

find out more. 

2 ALZHEIMER’S AND RELATED DEMENTIAS EDUCATION AND REFERRAL CENTER

Note that not all dementia symptoms are 

caused by Alzheimer’s, which currently has 

no cure, and no medications have been 

approved to treat this disease in people with 

Down syndrome. Medication side effects, 

depression, thyroid disease, and other 

conditions that can be treated and reversed 

may also cause dementia symptoms.

Down Syndrome and 

Alzheimer’s Research 

Alzheimer’s can last several years or 

more. Symptoms get worse over time and 

eventually result in death. Scientists are 

working hard to understand why some 

people with Down syndrome develop 

this dementia while others do not. They 

want to know how Alzheimer’s 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 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. 

Scientists are hopeful that research on 

Alzheimer’s and Down syndrome will not 

only help those with both conditions but 

may also lead to effective treatments for all 

people with Alzheimer’s.
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, possibly test new treatments, and 

access support and resources.

Volunteers and their caregivers should 

consider a study’s risks as well as its 

benefits. For example, a new drug being 

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. 

Not every clinical trial or study is right 

for every person. Studies have specific 

requirements that people must meet to 

participate. For example, studies may 

require participants to be 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. If you are not eligible for a specific 

study, there may be other opportunities. 

Family members and other caregivers 

play an important role for adults with 

Down syndrome who participate in clinical 

research. They may be asked to accompany 

the person to study visits, answer health 

questions about him or her, or provide 

consent or permission for the person with 

Down syndrome to take part in the study. 

Family members and caregivers may also be 

eligible to participate in studies themselves. 

“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 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:

• Learn about the Alzheimer’s Biomarkers 

Consortium-Down Syndrome (ABC-DS) 

and how to participate at 

www.nia.nih.gov/alzheimers/

clinical-trials/alzheimers-biomarkersconsortium-down-syndrome.

• Learn about the Alzheimer’s Clinical Trials 

Consortium-Down Syndrome (ACTC-DS) 

and how to participate at www.actc-ds.org.

• Join DS-Connect: The Down Syndrome 

Registry, 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 (NIH). You, your 

legally authorized representative, or your 

guardian can submit information about 

your health and, if desired, choose to be 

contacted about research opportunities. 

Visit https://dsconnect.nih.gov or email 

DSConnect@nih.gov for more information 

and to sign up.

• Learn about the INCLUDE (INvestigation 

of Co-occurring conditions across the 

Lifespan to Understand Down syndromE) 

project at www.nih.gov/include-project.

• Search NIA’s Alzheimer’s disease Clinical 

Trials Finder at www.alzheimers.gov.

• Visit NIH’s “Clinical Research Trials and 

You,” which includes a list of questions to 

consider before participating in a clinical 

trial at www.nih.gov/health-information/

nih-clinical-research-trials-you.

ALZHEIMER’S AND RELATED DEMENTIAS EDUCATION AND REFERRAL CENTER 3
For More Information 

Alzheimer’s and related Dementias 

Education and Referral (ADEAR) Center 

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 health 

professionals on Alzheimer’s disease and 

related dementias, including information on 

caregiving, clinical trials, and research. Staff 

members answer inquiries by phone, email, 

and in writing and make referrals to local 

and national resources. Visit the ADEAR 

website to learn more about Alzheimer’s 

and related dementias, find clinical trials, 

and sign up for email updates. 

Down Syndrome and 

Alzheimer’s Disease 

Alzheimer’s Association 

www.alz.org/alzheimers-dementia/

what-is-dementia/types-of-dementia/

down-syndrome

National Down Syndrome Society 

Publications 

www.ndss.org/about-down-syndrome/

publications

• Alzheimer’s Disease and Down Syndrome: 

A Practical Guidebook for Caregivers 

• Aging and Down Syndrome: A Health 

& Well-Being Guidebook 

National Down Syndrome Society 

Resources 

www.ndss.org/resources/alzheimers

Medical Care of Adults With Down 

Syndrome: A Clinical Guideline 

https://pubmed.ncbi.nlm.nih.gov/33079159

Down Syndrome Research

and Resources 

Down Syndrome:

Condition and Research Overview

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

downsyndrome

DS-Connect: The Down Syndrome Registry 

https://dsconnect.nih.gov

INCLUDE (INvestigation of Co-occurring 

conditions across the Lifespan to 

Understand Down syndromE) Project 

www.nih.gov/include-project

Global Down Syndrome Foundation 

www.globaldownsyndrome.org

National Down Syndrome Congress 

www.ndsccenter.org

LuMind IDSC Foundation 

www.lumindidsc.org

Other Alzheimer’s Resources 

Alzheimer’s Association 

800-272-3900 | www.alz.org

Alzheimer’s Foundation of America 

866-232-8484 | https://alzfdn.org

4 ALZHEIMER’S AND RELATED DEMENTIAS EDUCATION AND REFERRAL CENTER

National Institute on Aging

Eunice Kennedy Shriver National Institute of Child

Health and Human Development

National Institutes of Health

NIH...Turning Discovery Into Health®

NIH Publication No. 20-AG-8021 | November 2020 U.S. Department of Health and Human Services