Chronological age, but not FMRP levels, predicts neuropsychological performance in girls with fragile X syndrome.

The effect of FMRP levels and chronological age on executive functioning, visual-spatial abilities ,and verbal fluency tasks were examined in 46 school-age girls with fragile X syndrome (FXS). Results indicated that FMRP levels were not predictive of outcome on the neuropsychological tests but that performance on the executive functioning task tended to worsen with chronological age. This age effect was not observed on the tests of visual-spatial abilities or verbal fluency. These data indicate that relative deficits in executive functioning in girls with FXS become more pronounced with age. In contrast, the relative deficits in spatial and verbal abilities of these girls did not appear to increase with age, suggesting that these abilities may be spared. (c) 2006 Wiley-Liss, Inc.