RT Journal A1 Hampton T T1 REversing fragile x JF JAMA JO JAMA YR 2012 FD June 6 VO 307 IS 21 SP 2247 OP 2247 DO 10.1001/jama.2012.5440 UL http://dx.doi.org/10.1001/jama.2012.5440 AB Individuals with FXS have a single mutation in the FMR1 gene that prevents them from producing enough of the fragile X mental retardation protein. This leads to overactivation of a cell signaling pathway involving the metabotropic glutamate receptor 5 (mGlu5).