Alterations in midline cortical thickness and gyrification patterns mapped in children with 22q11.2 deletions

The 22q11.2 deletion syndrome (velocardiofacial/DiGeorge syndrome)is a neurogenetic condition associated with visuospatial deficits,as well as elevated rates of attentional disturbance, mood disorder,and psychosis. Previously, we detected pronounced cortical thinningin superior parietal and right parieto-occipital cortices inpatients with this syndrome, regions critical for visuospatialprocessing. Here we applied cortical pattern-matching algorithmsto structural magnetic resonance images obtained from 21 childrenwith confirmed 22q11.2 deletions (ages 8–17) and 13 demographicallymatched comparison subjects, in order to map cortical thicknessacross the medial hemispheric surfaces. In addition, corticalmodels were remeshed in frequency space to compute their surfacecomplexity. Cortical maps revealed a pattern of localized thinningin the ventromedial occipital–temporal cortex, criticalfor visuospatial representation, and the anterior cingulate,a key area for attentional control. However, children with 22q11.2DSshowed significantly increased gyral complexity bilaterallyin occipital cortex. Regional gray matter volumes, particularlyin medial frontal cortex, were strongly correlated with bothverbal and nonverbal cognitive functions. These findings suggestthat aberrant parieto-occipital brain development, as evidencedby both increased complexity and cortical thinning in theseregions, may be a neural substrate for the deficits in visuospatialand numerical understanding characteristic of this syndrome.