Another mediator that could link changes in GUS mRNA with PM size expansion may be mitochondrial dysfunction, which is itself related to: (i) increased levels of oxidative stress in PM carrier males with FXTAS as well as those with a Parkinsonism phenotype, (ii) elevated ASFMR1 expression8. Here, FMR1-AS1 is linked to fragile X-associated tremor/ataxia syndrome.