Following reevaluation of imaging, identified T2-fluid attenuation inversion recovery hyperintensity at the cerebellar peduncles, and further investigation of the family history revealing a 7-year-old grandson with fragile X syndrome (FXS), repeat genetic testing of the patient demonstrated 121 CGG repeats in the FMR1 gene, confirming the diagnosis of FXTAS. This evidence concerns the gene FMR1 and fragile X-associated tremor/ataxia syndrome.