Ubiquitin-immunoreactive granular inclusions in neuronal migration disorders

This report describes novel ubiquitin-immunoreactive inclusions in neurons in 3 out of 27 patients with neuronal migration disorders (NMDs). One patient was pathologically diagnosed as having cortical microdysgenesis, and the other two were consistent to have polymicrogyria. The inclusions were present in the perikaryon as compact granular structures, 0.5-2 microns in diameter. Since ubiquitin acts as a cellular scavenger and has a crucial role in selective protein degradation, the presence of ubiquitin-immunoreactive inclusions suggests that altered or abnormal proteins may accumulate in neurons in NMDs, although the nature of accumulated proteins remains unknown.