Several studies have shown that either genetic or pharmacological reduction of mGluR5 restores FXS related phenotypes in Fmr1 KO mice, including molecular, anatomical, electrophysiological and behavioral characteristics (Dölen et al., 2007; de Vrij et al., 2008; Osterweil et al., 2010; Thomas et al., 2011, 2012; Michalon et al., 2012; Gantois et al., 2013; Pop et al., 2014; Scharf et al., 2015; de Esch et al., 2015). Here, FMR1 is linked to fragile X syndrome.