FMR1 and fragile X-associated tremor/ataxia syndrome: Fragile X-associated Tremor/Ataxia syndrome (FXTAS) is characterized by adult-onset progressive intention tremor and gait ataxia affecting more than 33% of male and 10% of female carriers of expanded CGG triplets alleles in the premutation range (50-200 repeats) of the FMR1 gene and is uncoupled from FRAXA.