neurogenesis, differentiation and maturation of neurons were in progress within the subependymal germinal matrix of the 7-year-old autistic child. This interpretation of subependymal nodule genesis is consistent with lineage studies demonstrating that cells in nodules express cellular markers that are typical for progenitors derived from the subventricular germinal zone [35, 67]. However, in contrast to the subependymal nodules seen in subjects with tuberous sclerosis, in the examined autistic subject, the nodules seen were small (from 258 to 3,310 μm in diameter), and did not have the characteristic ovoid or polygonal giant cells, 80–150 μm in diameter, giant cells with multiple and peripherally displaced nuclei [25], or balloon cells, which are considered the sine qua non histopathological features of the cortical tubers and subependymal nodules observed in tuberous sclerosis [73].
