Are people who have Down syndrome at greater risk for developing Alzheimer's disease?

Yes, it appears that people with Down syndrome are at greater risk for developing Alzheimer’s disease. According to the Down Syndrome Society, Alzheimer’s disease is diagnosed in about 30 percent of people with Down syndrome in their 50s and in about 50 percent of those in their 60s.

Why are people with Down syndrome at greater risk for developing Alzheimer’s disease?

Scientists believe the increased risk is due to the extra chromosome, chromosome 21, that causes Down syndrome. Persons born with Down syndrome have three copies (instead of the normal two copies) of this chromosome. Scientists have identified several genes on chromosome 21 that are responsible for certain aspects of the aging process. They believe the extra full or partial chromosome contributes to the increased risk of Alzheimer’s disease seen in people with Down syndrome. In addition, genes on chromosome 21 produce a key protein, amyloid precursor protein, which plays an important role in the brain changes that are specifically seen in Alzheimer’s patients.

What are the symptoms of Alzheimer's disease in people with Down syndrome?

The symptoms of Alzheimer’s disease in people with Down syndrome may be different than those typically seen in others with Alzheimer’s disease. For example, in the early stages of the disease, memory loss may not be the first change noted. In fact, it may be difficult to notice symptoms of Alzheimer’s disease because of the already present limitations in memory and functioning in the person with Down syndrome. More often, the early changes seen in people with Down syndrome may be those affecting personality, behavior, and overall function.

More specifically, these symptoms may include:

  • Decreased interest in social interaction
  • Less interest in hobbies and previously “loved” activities and events
  • Increase in irritability, agitation, aggressiveness, sadness, anxiety
  • Loss of previously mastered skills
  • Changes in sleep pattern, more restlessness
  • Lowered attention span; loss of concentration
  • Increase in compulsions
  • Onset of negative and self-critical comments
  • Onset of confusion/disorientation
  • Loss of energy, tiredness, loss of “spark for life”
  • Loss of ability to complete tasks with multiple steps
  • Loss of balance/coordination when walking
  • Development of seizures

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