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Reviewed By Louise Chang, MD
June 28, 2007 -- Scientists report reversing symptoms of fragile X syndrome, a common genetic cause of autism and mental retardation, in lab tests on mice.
The findings may eventually lead to the development of drugs for fragile X syndrome and perhaps for autism, according to the researchers.
"Our study suggests that inhibiting a certain enzyme in the brain could be an effective therapy for countering the debilitating symptoms of FXS (fragile X syndrome) in children, and possibly in autistic kids as well," says researcher Mansuo Hayashi, PhD, in a Massachusetts Institute of Technology (MIT) news release.
Hayashi worked on the study while at MIT. She now works at Merck Research Laboratories in Boston.
The study appears in the online edition of Proceedings of the National Academy of Sciences.
What Is Fragile X Syndrome?
The National Institutes of Health defines fragile X syndrome as a genetic condition that causes a range of developmental problems including learning disabilities and mental retardation.
Fragile X syndrome is the most commonly inherited form of mental retardation and autism, note Hayashi and colleagues.
They studied mice born with fragile X syndrome. Those mice were hyperactive, had displayed repetitive behaviors, and lacked the normal anxiety of mice when put in an open area.
The scientists blocked a brain enzyme called PAK in the fragile X mice. That reduced fragile X symptoms.
That tactic hasn't been tested in people. But there are chemicals known to inhibit PAK.
"Our findings warrant testing of these inhibitors in FXS animal models with a hope of an eventual development of an FXS drug," write Hayashi and colleagues.
SOURCES: Hayashi, M. Proceedings of the National Academy of Sciences of the United States of America, July 3, 2007; vol 104: pp 11489-11494. News release, Massachusetts Institute of Technology.
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