Fragile X−associated tremor/ataxia syndrome (FXTAS) is a progressive, late-onset neurodegenerative disease that affects older carriers of premutation (CGG) repeat expansions of the fragile X mental retardation 1 (FMR1) gene. Clinical features include intention tremor, gait ataxia, memory loss, peripheral neuropathy, autonomic dysfunction, and parkinsonism. The presence of parkinsonism in FXTAS raises the possibility that some individuals who have Parkinson disease are actually carriers of a

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... utation FMR1 allele. Objective: To screen DNA samples from a large cohort of females with Parkinson disease for an excess of expanded alleles of the FMR1 gene. Design and Patients: We screened a cohort of 595 women with parkinsonism, the largest screening of a parkinsonism-associated group to date, for the presence of an FMR1 premutation allele (55-200 CGG repeats). The screening protocol uses an enhanced polymerase chain reaction method capable of flagging any FMR1 expanded CGG repeat in women as well as in men. Setting: Diagnostic assessments were performed at an outpatient tertiary clinic (Parkinson Institute, Milan). Genotyping was conducted at the University of California, Davis. Main Outcome Measures: CGG repeat number and clinical/neuroimaging assessments of patients with Parkinson disease were conducted. Two premutation carriers were identified.