FMR1 and fragile X-associated tremor/ataxia syndrome: The pathogenesis of FXTAS involve complex mechanisms including both RNA gain-of-functions by sequestration of RNA-binding factors (Sam68 (Sellier et al., 2010), PUR-alpha, hnRNP A2/B1, CUGBP1 (Jin et al., 2007; Sofola et al., 2007)) and protein gain-of-function by RAN translation of a poly-glycine-containing FMRP protein called FMRpolyG (Todd et al., 2013), which alter the ubiquitin proteasome system (Oh et al., 2015).