FMR1 and fragile X-associated tremor/ataxia syndrome: Moreover, FMR1 mRNA levels are even increased in FXTAS patients (Kenneson et al,2001; Allen et al,2004) and expression of CGG repeat RNA induces in vitro and in vivo neurotoxicity (Jin et al,2003; Willemsen et al,2003; Hukema et al,2014), suggesting a primary gain‐of‐function mechanism.