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New Clues on What Causes Aging
Genetics and DNA Damage
Play Role, Researchers Say.
By Miranda Hitti
WebMD
Medical News |
Ever wondered what causes aging? The
answer may lie in DNA.
DNA damage contributes to aging --
especially in people whose genes aren't good at
repairing damage, researchers report in
Nature.
"Damage, including DNA damage, drives
the functional decline we all experience as we age,"
says researcher Laura Niedernhofer, MD, PhD, in a
news release.
"But how we respond to that damage is
determined genetically," continues Niedernhofer, an
assistant professor of molecular genetics and
biochemistry at the University of Pittsburgh.
DNA can be damaged by normal wear and
tear, as well as from smoking, too much sunlight, or
other factors.
"The bottom line is that avoiding or
reducing DNA damage caused by sources such as
sunlight and cigarette smoke, as well as by our own
metabolism, also could delay aging," Niedernhofer
says.
Boy Is Clue to What Causes Aging
One of Niederhofer's colleagues on
the study was Jan Hoeijmakers, PhD, of Erasmus
Medical Center in Rotterdam, Netherlands.
Hoeijmakers had heard from doctors in
Germany about a 15-year-old Afghan boy with an
extreme form of premature aging, a condition called
progeria.
The boy was extremely sensitive to
sunlight and had had an old, wizened appearance
since age 10.
He was gaunt, had hearing loss and
vision problems, and had had hepatitis A and
tuberculosis as a young child.
The boy died when he was 16 after
getting severe pneumonia and having organ failure.
Genetic tests showed the boy had a
severe mutation in his XPF gene, a gene involved in
DNA repair.
Lab Tests
Based on those findings, Niedernhofer
and colleagues studied a mouse model of the aging
condition. They manipulated mice genetically to
mimic the rapid aging effect of the XPF mutation
seen in the boy.
This doesn't mean the XPF gene is the
only gene involved in progeria or in normal aging.
"However, it shows how important it
is to repair damage that is constantly inflicted on
our genes," Hoeijmakers says in the news release.
"It is fast becoming clear that
unraveling the complex biology of aging so as to
understand the true relationship between cause and
effect will not be easy," writes editorialist Tom
Kirkwood, PhD.
Kirkwood works in England at
Newcastle University's Institute for Ageing and
Health.
The XPF gene finding doesn't settle
all the questions about aging, but it "represents a
helpful buoy in these waters," Kirkwood writes.
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"Damage, including DNA damage, drives
the functional decline we all experience as we
age" |
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