FMR1 and fragile X-associated tremor/ataxia syndrome: The results demonstrate (a) that age-related declines in executive functions including visual working memory and inhibitory control, as well as manual movement speed, appear to be greater in male premutation carriers than controls without an FMR1 mutation, and (b) that the onset of the FXTAS disease process (“conversion”) is marked by subtle bradykinesia (slowing of movement) and possibly by changes in frontal-lobe mediated planning ability and working memory.