Down Syndrome and Increased Risk for Alzheimer’s

Adults with Down syndrome are living longer lives with increased well-being. In 2020, life expectancy in the United States was age 60, representing an increase of 35 years when compared to 1983.¹

As with all adults, advancing age increases the chances a person with Down syndrome will develop Alzheimer’s disease. According to the National Down Syndrome Society, about 30% of people with Down Syndrome who are in their 50s have Alzheimer’s disease. About 50% of people with Down syndrome in their 60s have Alzheimer’s disease.²

In observance of Sept. 21 as World Alzheimer’s Day and recognition that people with Down syndrome have an increased risk of developing Alzheimer’s, CDC and its partners are focused on sharing information and resources to help support people with Down syndrome, their families, caregivers, health care providers, and public health professionals. Estimates for the number of people with Down syndrome in the United States have grown from nearly 50,000 in 1950 to 206,366 in 2010.³ Some estimates put the worldwide population of people with Down syndrome at more than 6 million.⁴

Down Syndrome occurs when an individual has an extra partial, or whole, copy of chromosome 21. It is not yet known why this syndrome occurs, but Down syndrome has always been part of the human condition. It exists in all regions across the globe and commonly affects learning styles, physical characteristics and health.⁵

Scientists think the increased risk of Alzheimer’s disease among people with Down syndrome results from the extra genes present as well as other health issues such as congenital heart defects.

• 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, amyloid protein, involved with changes in the brain associated with Alzheimer’s. The build-up of amyloid protein in the brain disrupts the way brain cells communicate to each other. Amyloid accumulation is seen in almost all adults over 40 with Down syndrome. Despite these brain changes, not everyone with Down syndrome develops Alzheimer’s symptoms.
• People with Down syndrome are extremely likely to experience severe issues related to their heart, which places them at increased risk for early onset dementia. About 50% of people with Down syndrome have a congenital heart defect – a condition rarely seen in the general population.

Additionally, adults with Down syndrome experience “accelerated aging,” meaning that in their 40s and 50s, they experience certain conditions that are more commonly seen in much older adults in the general population. These conditions may include:

• Changes in behavior, such as reduced interest in being sociable, conversing or expressing thoughts; irritability, uncooperativeness or aggression; sadness, fearfulness or anxiety;⁴
• Seizures that begin in adulthood;
• Changes in coordination and walking;
• An increase in care needs such as a person’s safety as they navigate their environment; and
• Full dependency for all personal care (bathing, dressing, toileting).

Many people with Down syndrome are diagnosed with Alzheimer’s disease in their 50s, but it is not uncommon for symptoms to occur in their late 40s. The presence of Alzheimer’s disease in people with Down syndrome can lead to a rapid, progressive decline in brain health. And, like most people diagnosed with Alzheimer’s disease, there are variables as to the onset of symptoms and the progression of the disease. Many family members and caregivers observe that people with Down syndrome appear to “slow down” in their late 40s and 50s.

Most adults with Down syndrome do not self-report concerns about memory. Diagnosing Alzheimer’s disease in a person with Down syndrome can be difficult because of the challenges involved in assessing thinking-skill changes in persons with intellectual disabilities. For this reason, information from a caregiver or close family member can be especially helpful for the health care provider during the diagnostic process. Caregivers, for example, can watch for changes in day-to-day function.

Many resources are available to support caregivers and health care providers.

• Alzheimer’s Disease and Down Syndrome: A Practical Guidebook for Caregivers. Available in English, Spanish, and Dutch. This guidebook from the National Down Syndrome Society was written to address specific concerns related to adults with Down syndrome and Alzheimer’s disease and the people who love and support them. It provides information about the connection between Down syndrome and Alzheimer’s disease and offers suggestions about how to carefully and thoughtfully evaluate changes that may be observed with aging, and guidance about how to adapt and thrive in an ever-changing caregiving role when a diagnosis is made.
• Aging and Down Syndrome: A Health and Wellbeing Guidebook. The booklet is intended to be used by families, professionals, direct caregivers, or anyone concerned with the general welfare of someone with Down syndrome.

• Medical Care of Adults with Down Syndrome, A Clinical Guideline. JAMA. 2020;324(15):1543-1556. doi:10.1001/jama.2020.17024

• Alzheimer’s Disease Medications Fact Sheet (en espanol) https://www.nia.nih.gov/health/how-alzheimers-disease-treated

• Alzheimer’s Association, Down Syndrome and Alzheimer’s Disease. https://www.alz.org/alzheimers-dementia/what-is-dementia/types-of-dementia/down-syndrome
• National Down Syndrome Society, Alzheimer’s Disease & Down Syndrome. https://www.ndss.org/resources/alzheimers/
• National Institute on Aging, Alzheimer’s Disease in People with Down Syndrome. https://www.nia.nih.gov/health/alzheimers-disease-people-down-syndrome