Selective spatial processing deficits in an at-risk subgroup of the fragile X premutation

Until a decade ago, it was assumed that males with the fragile X premutation were unaffected by any cognitive phenotype. Here we examined the extent to which CGG repeat toxicity extends to visuospatial functioning in male fragile X premutation carriers who are asymptomatic for a late-onset neurodegenerative disorder, fragile X-associated tremor/ataxia syndrome (FXTAS). Thirty-three premutation males aged 20?68 years [divided into two groups: 16 low-repeat carriers (CGG ? 55? <100) and 17 high-repeat carriers (CGG > 100)] with a family history of fragile X syndrome and 62 non-affected adult males with normal FMR1 alleles were recruited