Alzheimer’s Disease & Down Syndrome

You can read our comprehensive Alzheimer’s Disease and Down Syndrome Guidebook here.

  • You can view our most recent webinar "Alzheimer's disease in people with Down syndrome: What we know and what we can do about it" here.

Adults with Down syndrome are at increased risk of Alzheimer’s disease as they grow older.  But not all changes in behavior or loss of skill are due to Alzheimer’s disease. If you notice differences in your loved one, please contact their doctor. A thoughtful approach is very important.

The Connection Between Alzheimer’s Disease and Down Syndrome

Down syndrome occurs when an individual has a full or partial third copy of chromosome 21. Typically, people have two copies of each chromosome. Chromosome 21 plays a key role in the relationship between Down syndrome and Alzheimer’s disease as it carries a gene that produces one of the key proteins involved with changes in the brain caused by Alzheimer’s. Additionally, scientists have located several genes on chromosome 21 that are involved in the aging process and that contribute to the increased risk of Alzheimer’s disease. It is this unique property of chromosome 21 that makes the disease a more acute concern for people with Down syndrome than those with other forms of intellectual disability.

General Definition and Overview

Michael de Jesus and friends

Alzheimer’s disease is a type of dementia that gradually destroys brain cells, affecting a person’s memory and their ability to learn, make judgments, communicate, and carry out basic daily activities. Alzheimer’s disease is characterized by a gradual decline that generally progresses through three stages: early, middle, and late-stage disease. These three stages are distinguished by their general features, which tend to progress gradually throughout the course of the disease. Alzheimer’s disease is not inevitable in people with Down syndrome. While all people with Down syndrome are at risk, many adults with Down syndrome will not show the cognitive changes of Alzheimer’s disease in their lifetime. This is why it is especially important to be careful and thoughtful about assigning this diagnosis before looking at all other possible causes for why changes are taking place with aging. Physical signs of Alzheimer's disease, including amyloid plaques and tangles in the brain, are present in almost all individuals with Down syndrome by age 40 years, most individuals will not show symptoms of dementia for another decade or more. The risk of developing Alzheimer's disease increases with each decade of life after age 40, and the overall lifetime risk of developing Alzheimer's disease is more than 90% (Fortea et al., 2021*).

*Juan Fortea, Shahid H Zaman, Sigan Hartley, Michael S Rafii, Elizabeth Head, Maria Carmona-Iragui, Alzheimer's disease associated with Down syndrome: a genetic form of dementia, The Lancet Neurology, Volume 20, Issue 11, 2021, Pages 930-942, ISSN 1474-4422,

The Span of Alzheimer's Disease

Alzheimer’s disease is a progressive disease, gradually and steadily moving from early, to middle, to late stage.  As the disease progresses, it is expected that different abilities and skills may be compromised and the need for support and supervision increases, so aim to prepare proactively for each step.

Early Stage

  • Short-term memory loss (difficulty recalling recent events, learning and remembering names, and keeping track of the day or date; asking repeated questions or telling the same story repeatedly)
  • Difficulty learning and retrieving new information
  • Expressive language changes (word finding difficulties, smaller vocabulary, shorter phrases, less spontaneous speech)
  • Receptive language changes (difficulty understanding language and verbal instructions)
  • Worsened ability to plan and sequence familiar tasks
  • Behavior changes
  • Personality changes
  • Spatial disorientation (difficulty navigating familiar areas)
  • Worsened fine motor control
  • Decline in work productivity
  • Difficulty doing complex tasks requiring multiple steps (including household chores and other daily activities)
  • Depressed mood

Middle Stage

  • Decreased ability to perform everyday tasks and self-care skills
  • Worsened short-term memory with generally preserved long-term memory
  • Increased disorientation to time and place
  • Worsened ability to express and understand language (vocabulary shrinks even further, communicates in short phrases or single words)
  • Difficulty recognizing familiar people and objects
  • Poor judgment and worsened attention to personal safety
  • Mood and behavior fluctuations (anxiety, paranoia, hallucinations, restlessness, agitation, wandering)
  • Physical changes related to progression of the disease including: new onset seizures, urinary incontinence and possible fecal incontinence, swallowing dysfunction, mobility changes (difficulty with walking and poor depth perception)

Advanced Stage

  • Significant memory impairment (loss of short-term and long-term memory, loss of recognition of family members and familiar faces)
  • Dependency on others for all personal care tasks (bathing, dressing, toileting, and eventually, eating)
  • Increased immobility with eventual dependence on a wheelchair or bed
  • Profound loss of speech (minimal words or sounds)
  • Loss of mechanics of chewing and swallowing, leading to aspiration events and pneumonias
  • Full incontinence (both urinary and fecal)

Recognizing Alzheimer's Disease

Establishing a "Baseline"

Most adults with Down syndrome will not self-report concerns about memory. Instead, it will take an astute caregiver who knows the individual well to identify early changes or concerns and bring them to the attention of a medical professional. Alzheimer’s disease is suspected when there is a change or a series of changes seen in an individual as compared to their previous level of functioning. Thus, in order to observe change effectively, one must be informed about what the individual was capable of doing at his or her very best. This could be considered the individual’s “baseline.”

The primary importance of having a good description and understanding of an individual’s baseline is so it can be used as a basis of comparison if changes are observed as the individual grows older. It is extremely helpful to record baseline information throughout adulthood – noting basic self-care skills, personal achievements, academic and employment milestones, talents, skills, and hobbies. A baseline can also be established formally at an office visit with a memory specialist, where these components can be reviewed and memory abilities can be tested.

Formal screening for memory concerns should be a priority throughout mid-to later-adulthood. Alzheimer’s disease is a clinical diagnosis. That means that it requires a doctor to make the diagnosis based on their judgment. There is no single blood test, x-ray, or brain scan that will make or confirm the diagnosis. The diagnosis depends largely on an accurate history detailing progressive loss of memory and daily functioning. It is vitally important that a history be provided by someone (a family member, a longtime caregiver, etc.) who knows the person well. It is important to seek the opinion of a specialist who will take all factors into account to arrive at a diagnosis thoughtfully. It is worth the effort to not rush the diagnosis. Make sure that the assessment has been thorough and that all other possibilities were given careful consideration. Note that many of the common conditions related to aging and Down syndrome outlined in the beginning of this article can be mistaken as dementia if not identified properly (hearing loss, low thyroid function, vision loss, pain, sleep apnea, etc.). If the individual is showing change compared to their baseline memory or functioning, it is important to consult with the primary care doctor to assess for the presence of these other potentially treatable or correctable conditions.

Seeking A Memory Evaluation

Look for a memory specialist (a geriatrician, neurologist, psychiatrist, or neuropsychologist). Ideally, the specialist would have experience assessing individuals with intellectual disabilities. Assessments should be comprehensive and adapted appropriately for each person’s baseline intellectual disability. A thorough assessment should take into account all other potential contributing factors (medical, psychiatric, environmental, social) that could also account for, or contribute to, the reported changes.

After The Diagnosis Is Made

First, make sure that the diagnosis seems accurate. Was it arrived upon in a thoughtful and thorough manner, carefully excluding other possible causes that may explain the changes that were observed and reported?

Next, be proactive in building a support network. The key feature of Alzheimer’s disease is that it is a progressive disorder, meaning it is expected that the individual’s needs are going to increase over time. The support network encompasses the primary care doctor, memory specialist and other related medical specialists, caregivers, day program or workshop staff, state or agency support staff, other family, friends, etc.

Learn About Dementia

This article aims to provide a basic introduction to this topic, but one should seek out other resources to learn more and to get support. Some resources are provided at the end of this page.

Additional Resources

External Resources


  • Adults with Down Syndrome. Pueschel, S. M. Baltimore, MD: Brookes Publishing. (2006)
  • Alzheimer’s Disease and Dementia in Down Syndrome and Intellectual Disabilities. Prasher, V. P. Radcliffe Publishing. (2005)
  • The Dementias: Hope Through Research. The National Institute of Neurological Disorders and Stroke and the National Institute on Aging. (2013) 
  • Mental Wellness in Adults with Down Syndrome. McGuire, D. and Chicoine, B. Bethesda, MD: Woodbine House. (2005)