Neuropathological evaluation of serial coronal hemispheric sections from the cerebral and cerebellar hemispheres of 13 autistic and 14 control subjects revealed more details characterizing the topography and severity of changes than did standard sampling of brains for routine neuropathological evaluation. A broad range of changes was found. Developmental abnormalities included subependymal nodular dysplasia, heterotopia and very common dysplastic changes within the neo- and archicortex, hippocampus and cerebellum in 12 of 13 examined brains of the autistic subjects (92%) (Table 2). The general result of these developmental defects was a multifocal disorganization of gray and white matter. The developmental pathology observed in control brains was limited to one cerebellar dysplasia.
