For example, fragile X-associated tremor/ataxia syndrome (FXTAS), caused by an intermediate premutation length CGG repeat expansion in the promoter of the FMR1 gene, is a neurodegenerative disorder that typically manifests after the age of 55, with age-dependent penetrance and progressive clinical features (65–67). The gene discussed is FMR1; the disease is fragile X-associated tremor/ataxia syndrome.