FMR1 and fragile X-associated tremor/ataxia syndrome: Fragile X-associated Tremor/Ataxia Syndrome (FXTAS) is a late-onset neurodegenerative disorder with an average age of onset of 62 that affects carriers of a premutation (PM) allele (55–200 CGG repeats) in the fragile X messenger ribonucleoprotein 1 (FMR1) gene, usually presenting with a more severe clinical phenotype in males, likely due to the presence of a second X chromosome in females [1,2].