FXTAS: a progressive neurologic syndrome associated with Fragile X premutation.

The FMR1 gene is involved in two different syndromes: Fragile X syndrome and Fragile X-associated tremor/ataxia syndrome (FXTAS). Fragile X syndrome is a childhood disease and is associated with mental retardation as the main clinical characteristic, whereas FXTAS develops in men and women over 50 years of age. FXTAS represents a new form of inclusion disorder with a high prevalence in the general population. The neurologic phenotype of FXTAS includes intention tremor and ataxia. Associated features are dementia, parkinsonism, neuropathy, and autonomic dysfunction. Elevated FMR1 transcripts have been proposed as the molecular basis of the pathogenic mechanism leading to FXTAS. This review discusses recent developments in the clinical phenotype, prevalence and screening, animal models, and molecular mechanisms of RNA-based pathogenesis in FXTAS.