There is evidence that the absence of FMRP leads to dysregulation of several ion channels, including L-type voltage-gated calcium channels (Meredith et al., 2007; Castagnola et al., 2018; Danesi et al., 2018) and potassium (K+) channels (Brown et al., 2010; Deng et al., 2013), which may contribute to defects in cellular excitability and neuronal plasticity in FXS. This evidence concerns the gene FMR1 and fragile X syndrome.