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Genetic and Rare Diseases Information Center (GARD)

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Alzheimer disease


* Not a rare disease
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Alzheimer disease is a degenerative disease of the brain that causes gradual loss of memory, judgment, and ability to function socially. Alzheimer disease currently affects about 5 million people.[1] About 75 percent of Alzheimer disease cases are classified as sporadic, which means they occur in people with no history of the disorder in their family. Although the cause of these cases is unknown, genetic changes are likely to play a role. Virtually all sporadic Alzheimer disease begins after age 65, and the risk of developing this condition increases as a person gets older.

The remaining cases of Alzheimer disease are familial, which means they are found in multiple members of a family. Familial Alzheimer disease can be divided into early-onset disease (symptoms begin before age 65) and late-onset disease (symptoms begin after age 65).[2]

Last updated: 7/2/2013


  1. Alzheimer Disease. Genetics Home Reference. October 2006; Accessed 1/18/2008.
  2. Alzheimer's Facts and Figures. Alzheimer's association. October 16, 2007; Accessed 1/18/2008.
Your Questions Answered
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Please contact us with your questions about Alzheimer disease. We will answer your question and update these pages with new resources and information.

Basic Information

Resources for Kids

  • The Alzherimer's Association provides videos and information to help kids and teens deal with the emotions and reactions that are common when a loved one is diagnosed with Alzheimer’s. Click on Alzheimer's Association to view these resources.

Press Releases


  • Learn how Alzheimer's disease affects the brain through the Alzheimer's Association's interactive Brain Tour

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