The current state of knowledge indicates that the neuronal death observed in FXTAS patients is directly linked to the non-AUG (RAN) translated polyglycine (FMRpolyG), generated from the FMR1 transcript adjacently to fragile X mental retardation protein (FMRP) (Todd et al., 2013; Buijsen et al., 2014; Hukema et al., 2015; Buijsen et al., 2016; Sellier et al., 2017). This evidence concerns the gene FMR1 and fragile X-associated tremor/ataxia syndrome.