Cognition and lobar morphology in full mutation boys with fragile X syndrome

The aims of the present study are twofold: (1) to examine cortical morphology (CM) associated with alterations in cognition in fragile X syndrome (FXS); (2) to characterize the CM profile of FXS versus FXS with an autism diagnosis (FXS + Aut) as a preliminary attempt to further elucidate the behavioral distinctions between the two sub-groups. We used anatomical magnetic resonance imaging surface-based morphometry in 21 male children (FXS N = 11 and age [2.27–13.3] matched controls [C] N = 10). We found (1) increased whole hemispheric and lobar cortical volume, cortical thickness and cortical complexity bilaterally, yet insignificant changes in hemispheric surface area and gyrification index in FXS compared to C; (2) linear regression analyses revealed significant negative correlations between CM and cognition; (3) significant CM differences between FXS and FXS + Aut associated with their distinctive behavioral phenotypes. These findings are critical in understanding the neuropathophysiology of one of the most common intellectual deficiency syndromes associated with altered cognition as they provide human in vivo information about genetic control of CM and cognition.

The increase in cortical morphology due, in part, to decreased pruning correlates negatively with cognitive performance in fragile X syndrome.Figure optionsDownload high-quality image (278 K)Download as PowerPoint slideHighlights
► FXS provides a privileged venue for investigating gene–brain–behavior.
► Neuroimaging FXS relatively focused on measuring subcortical structures.
► Here we focus on the cerebral cortical morphology (CM).
► We report increased lobar volume, thickness and complexity in FXS.
► CM differs between FXS and FXS + Aut associated with distinctive cognition.