Facts about the connection between Down syndrome and Alzheimer’s Disease

Down syndrome occurs when a person has three copies of the 21st chromosome instead of the normal two copies. Studies show that one the main genes responsible for Alzheimer’s disease is on the 21st chromosome and is therefore more active in individuals with Down syndrome.

  • Numerous studies have shown that because of their extra copy of the Alzheimer gene, virtually 100% of people with Down syndrome will develop the pathology (plaques and tangles) in the brain associated with Alzheimer’s disease (but not necessarily the same memory loss).
  • Although more research needs to be done, it is estimated that about 50% of people with Down syndrome will develop the memory problems of Alzheimer’s disease before age 50.
  • 5.4 million Americans are living with Alzheimer’s disease now and that will rise to over 13 million by 2050. One in eight older Americans has Alzheimer’s disease.

Research on people with Down syndrome can lead to better treatments for people with Alzheimer’s disease. For example:

  • Additional studies on the 21st chromosome could lead to better ways to test the population to identify Alzheimer’s disease prior to the onset of symptoms.
  • New potential drugs can be tested in people with Down syndrome before the onset of any dementia symptoms because they have such a high incidence of Alzheimer’s disease. This could lead to the development of drugs for typical people who are at high risk of developing Alzheimer’s disease so as to avoid or delay the onset of symptoms.

Clearly, this is an important area of research for people with Down syndrome and Alzheimer’s, and the Global Down Syndrome Foundation is committed to ensuring such research happens.