New Clues on What Causes Aging

Genetics and DNA Damage Play Role, Researchers Say

Medically Reviewed by Louise Chang, MD on December 21, 2006

Dec. 20, 2006 -- Ever wondered what causes aging? The answer may lie inDNA.

DNA damage contributes to aging -- especially in people whose genes aren'tgood at repairing damage, researchers report in Nature.

"Damage, including DNA damage, drives the functional decline we allexperience as we age," says researcher Laura Niedernhofer, MD, PhD, in anews release.

"But how we respond to that damage is determined genetically,"continues Niedernhofer, an assistant professor of molecular genetics andbiochemistry at the University of Pittsburgh.

DNA can be damaged by normal wear and tear, as well as from smoking, toomuch sunlight, or other factors.

"The bottom line is that avoiding or reducing DNA damage caused bysources 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, ofErasmus Medical Center in Rotterdam, Netherlands.

Hoeijmakers had heard from doctors in Germany about a 15-year-old Afghan boywith an extreme form of premature aging, a condition called progeria.

The boy was extremely sensitive to sunlight and had had an old, wizenedappearance since age 10.

He was gaunt, had hearing loss and vision problems, and had had hepatitisA andtuberculosis 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 geneinvolved in DNA repair.

Lab Tests

Based on those findings, Niedernhofer and colleagues studied a mouse modelof the aging condition. They manipulated mice genetically to mimic the rapidaging effect of the XPF mutation seen in the boy.

This doesn't mean the XPF gene is the only gene involved in progeria or innormal aging.

"However, it shows how important it is to repair damage that isconstantly inflicted on our genes," Hoeijmakers says in the newsrelease.

"It is fast becoming clear that unraveling the complex biology of agingso as to understand the true relationship between cause and effect will not beeasy," writes editorialist Tom Kirkwood, PhD.

Kirkwood works in England at Newcastle University's Institute for Ageing andHealth.

The XPF gene finding doesn't settle all the questions about aging, but it"represents a helpful buoy in these waters," Kirkwood writes.

Show Sources

SOURCES: Niedernhofer, L. Nature, Dec. 21, 2006; vol 444: pp 1038-1043. Kirkwood, T. Nature, Dec. 21, 2006; vol 444: p 1015. News release, University of Pittsburgh Medical Center. News release, Nature.

© 2006 WebMD, Inc. All rights reserved. View privacy policy and trust info