Objective. p83 is an 83 kDa CNS-specific, development-regulated protein. Identifying the involvement of p83 in human CNS processes is a required step towards understanding its biological roles. A premade cDNA rat cerebellum expression library has been screened, using a specific antibody to isolate p83 cDNA. The nucleotide sequence showed identity with Drebrin A. Drebrin A and E isoforms were detected in adults and embryos. Drebrin A is a neuron-specific, development-regulated actin-binding protein. It participates in growth cone extension and dendritic spine formation. Drebrin and p83 bind to heat shock protein 90b, among other properties in common. The analysis of the correspondence between p83 and drebrin A is in progress. We report here the expression of drebrin in CFD type Taylor IIB as compared to normal cortex. Materials and methods. Tissue sections were stained with hematoxylin-eosin and silver (Bielchowsky). Sections were processed for immunohistochemistry using an anti-drebrin antibody, and an antigen retrieval technique. Detection was carried out using a biotinylated antibody, using DAB as chromogen. Dysplastic tissue was obtained at surgery for epilepsy. Controls were obtained at autopsy from patients without history of neurological disorder and gross pathological changes. Results and Conclusions. A specific drebrin labeling in dysplastic tissue was more intense than in controls. Indeed, most control section exhibited at most a slightly higher staining than the background. Balloon, clear and undetermined cells, and gigantic, dysmorphic neurons, showed a conspicuous labeling by anti-drebrin. These cells showed a thin rim labeling of the nuclear membrane, and a finely punctate nuclear labeling. In contrast, a coarse nuclear, but a faint cytoplasm labeling was observed in autopsy cases. Our data suggest an association between Drebrin expression and the Taylor type IIB CFD, a disturbance of cortical development. Supported by FAPESP, CNPq and FAEPA