Fragile X Syndrome: Gene Fix?

Tweaking a Certain Gene Eases Fragile X Symptoms in Lab Tests on Mice

By Miranda Hitti
WebMD Health News

Reviewed By Louise Chang, MD

Dec. 19, 2007 -- Scientists may have found a genetic key to treating fragile X syndrome.

Fragile X syndrome is the most common form of inherited mental retardation and is associated with autism.

"These findings have major therapeutic implications for fragile X syndrome and autism," the researchers write in tomorrow's edition of Neuron.

Such therapies aren't ready for use in people yet.

In lab tests, the scientists tweaked the DNA of mice with fragile X syndrome. The goal was to make a certain mouse gene halve its production of a protein called mGluR5.

Reducing production of that protein eased fragile X syndrome symptoms including seizures and problems with the eye, nerves, brain, memory, and body growth.

"A simple way to conceptualize the constellation of findings is that fragile X syndrome is a disorder of excess ... and these excesses can be corrected by reducing mGluR5," write the researchers.

They included graduate student Gul Dolen and Mark Bear, PhD, Picower Professor of Neuroscience and the director of the Picower Institute for Learning and Memory at the Massachusetts Institute of Technology (MIT).

"It is remarkable that by reducing mGluR5 gene dosage by 50%, we were able to bring multiple, widely varied fragile X phenotypes [symptoms] significantly closer to normal," write the researchers.

An MIT news release notes that while the experiment involved genetic engineering, drugs designed to do the same thing will soon be tested in people.

SOURCES: Dolen, G, Neuron, Dec. 20, 2007; vol 56: pp 955-962. News release, Massachusetts Institute of Technology. News release, Cell Press.

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