FMR1 and fragile X-associated tremor/ataxia syndrome: In pre-mutation carriers, FMR1 mRNA levels are elevated 2–10 fold; this finding has been noted in both FXTAS and asymptomatic pre-mutation carrier lymphocytes and fibroblasts, transformed lymphoblastoid cell lines, the brains of expanded CGG-FMR1 knock-in mouse models, and FXTAS patient brains [5], [10], [11], [48].