FMR1 and fragile X syndrome: Glyx-13 has recently been shown to preferentially target GluN2B-containing receptors at an allosteric site distinct from the glutamate- and glycine-binding sites.52,53 Furthermore, it is known to be a cognitive enhancer in several learning and memory paradigms.54–56 To test the potential utility of augmenting GluN2B function in FXS, we treated Fmr1 KO and WT hippocampal slices with Glyx-13 (0.1 μM) and measured protein synthesis levels (Figure 7A).