At present, the onset and development of FXTAS is explained by two main mechanisms (Botta-Orfila et al., 2016): (i) RNA-mediated sequestration, and subsequent inactivation, of proteins attracted by the CGG trinucleotide repeats in the 5′ UTR region of FMR1 RNA and (ii) toxic aggregation of Repeat-Associated Non-AUG (RAN) polyglycine peptides translated from the FMR1 5′ UTR (FMRpolyG; Figure 1). This evidence concerns the gene FMR1 and fragile X-associated tremor/ataxia syndrome.