Additionally, while much attention in FXS has focused upon mGluR5 receptors and enhanced mGluR-dependent long term depression (LTD) seen in fmr1 KO mice, FMRP binds over 400 putative mRNAs (Ashley et al., 1993) and various approaches similarly identify several other potassium channel mRNAs as FMRP targets (Lee and Jan, 2012). Here, FMR1 is linked to fragile X syndrome.