Reduced activity of mGluR5 protein helps Fragile X syndrome

Fragile X syndrome is the most common inherited form of mental retardation and the leading identified cause of autism. Fragile X syndrome is caused by lack of activity of the FMR1 gene, which is responsible for a protein called FMRP. Without FMRP, a protein called mGluR5 goes unchecked, and it has been theorized that this plays an important part in Fragile X syndrome.

To test this theory, researchers used mice without an active FMR1 gene (like in Fragile X syndrome) but with a reduced amount of mGluR5 protein. These mice showed an improvement in their brain structure and function, in their brains' ability to make key proteins, and in memory and body growth. This shows that the overproduction of mGluR5 is very important in Fragile X syndrome, and suggests a path for drug development to treat the syndrome.

Dolen, Gul, Emily Osterweil, B.S. Shankaranarayana Rao, Gordon B. Smith, Benjamin D. Auerbach, Sumantra Chattarji, & Mark F. Bear. "Correction of Fragile X Syndrome in Mice." Neuron 56(2007): 955-962.