Q: Why is someone with Down syndrome at greater risk
for Alzheimer’s disease?
A: We know that the presence
of amyloid plaques in the brain is often associated with the development of
Alzheimer’s disease. The gene that codes for the amyloid protein is on the 21st
chromosome. Since individuals with Down syndrome are born with three copies of the 21st
chromosome, it’s likely that they are making a greater amount of amyloid then do
individuals in the general population. As a result, a significant number of
adults with Down syndrome develop signs of Alzheimer’s disease when they reach
middle age.
Q: But not everyone
with Down syndrome will develop dementia, right?
A: That’s correct – and some healthy individuals develop significant levels
of amyloid plaque in their brains and don’t show signs of dementia. We still have a lot to learn in this field. But it’s very unusual to have a population
where half of the individuals will develop a disease. That means studying the Down syndrome
population may help us shed some additional light on what causes Alzheimer’s
disease – and how we can prevent and/or cure it.
Q: What research is
currently being conducted to learn more about this connection?
A: We’re
currently conducting a study titled “Natural History of
Amyloid Deposition in Adults with Down Syndrome.” The goal is to evaluate individuals with Down
syndrome who are free of symptoms of dementia or Alzheimer’s disease and to
follow them for five or more years. The
study involves both neuropsychological testing and imaging amyloid via scans of
the brain.
Q: What do you hope
to determine from this study?
A: Our hope is to
begin to understand how early cognitive, adaptive and behavioral signs of
Alzheimer’s disease are related to amyloid deposition in the brain. In
addition, we hope to identify factors that may increase the chances that an
individual will develop Alzheimer’s as well as factors that may be protective
for individuals.
Labels: Alzheimer's disease, Down syndrome, University of Pittsburgh School of Medicine
