FMR1 and fragile X-associated tremor/ataxia syndrome: Overall, the prevalence of FMR1 expansions in populations being evaluated for movement disorders is low (<2%) but this could be explained by several factors such as lack of insight of patients with FXTAS into their symptoms resulting in them not reporting their neurological symptoms [36] and the fact that few patients with FXTAS are being referred to and evaluated by a movement disorder specialist [37].