FMR1 and fragile X-associated tremor/ataxia syndrome: In addition, abnormalities of white matter of those FXTAS patients were identified to be strongly correlated with the increase in FMR1 mRNA level.39,40 In our study, no significant change of the Fmr1 mRNA levels was found in the FMRP-P608L mice, which may also be one of the reasons that the MRI scans of this patient did not exhibit abnormalities.