Heterotopia in Individuals with 22q11.2 Deletion Syndrome

Representative examples of morphometric findings in brain MRIs of 6 subjects with 22q11.2DS. Subject 1: Small cysts adjacent to the anterior horns of the lateral ventricles (A). Subject 2: T1WI (B) and T2*WI (C) of bilateral cysts (black arrows, isointense to CSF in both sequences) and periventricular heterotopia (white arrows, cortex-isointense in both sequences). Subject 3: Multiple, perivascular, and frontal heterotopia in the white matter (D). Subject 4: Multiple periventricular heterotopia forming an arcuate structure in the sagittal view with a remarkable overlap with the migratory stream of the Arc cells outlined in G (E, F, and G). The drawing in G is taken from Paredes et al²¹ (reprinted with permission from American Association for the Advancement of Science), who were the first to identify Arc cells as a population of late-moving neurons at this localization. Subjects 5 and 6: Exemplary Mercator brain projections of 2 of the 3 individuals with polymicrogyria in the peri-Sylvian area of the right hemisphere (H and I).