The absence of FMRP in Fmr1 KO mouse results in rapid dephosphorylation of ERK upon mGluR1/5 stimulation suggesting that over-activation of phosphatases in synapses affects the synaptic translation, transcription, and synaptic receptor regulation in FXS [53,119,140,141]. This evidence concerns the gene FMR1 and fragile X syndrome.