New Clues on What Causes Aging
Genetics and DNA Damage Play Role, Researchers Say
Dec. 20, 2006 -- Ever wondered what causes aging? The answer may lie in
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
"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 hepatitisA 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.
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
"However, it shows how important it is to repair damage that is
constantly inflicted on our genes," Hoeijmakers says in the news
"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
The XPF gene finding doesn't settle all the questions about aging, but it
"represents a helpful buoy in these waters," Kirkwood writes.