Structure in lissencephaly determined by immunohistochemical staining.

The brains of patients with lissencephaly were examined by peroxidase-antiperoxidase immunohistochemical staining of synaptophysin, myelin basic protein, and glial fibrillary acidic protein. In contrast to the normal cortical pattern, the cortex, with a smooth surface, demonstrated quite different staining patterns in the molecular, superficial cellular, sparsely cellular, and deep cellular layers. The molecular layer was abnormally positive with synaptophysin staining. The superficial cellular layer was also diffusely stained for synaptophysin; there was a positive reaction in the linearly arranged myelin sheaths. The sparsely cellular layer revealed less staining for synaptophysin, but was perivascularly positive for glial fibrillary acidic protein. In the deep cellular layer, synaptophysin staining had multiple neuronal columns and myelin basic protein-staining had a reticular pattern around neuronal columns. These results suggest that the sparsely cellular layer may correspond to the molecular layer and white matter in normal brain; neurons with forming myelin sheaths in the superficial cellular layer regularly penetrate the surface of the molecular layer, forming arrested cortical columns in the deep cellular layer.