Two studies tested the specificity of the neurocognitive profile of women w
ith fragile X syndrome (FXS). First, women with an FXS full mutation were c
ompared with women with a premutation and women without FXS who grew up in
FXS families. Women with FXS had a significantly lower IQ than the other gr
oups, and analyses of subtest profiles showed they had a relative weakness
on Arithmetic and strength on Picture Completion. Women with FXS performed
worse than the other groups on executive function, spatial ability, and vis
ual memory. Next, women with FXS were compared with women without FXS match
ed on age and IQ. A similar IQ profile was found, but women with FXS were w
orse than controls only on executive function. The authors also examined wh
ich neurocognitive indices were related to the underlying biology of the di
sorder. Overall, the results indicated that executive rather than visuospat
ial deficits were primary in the neurocognitive profile of FXS.