CELLULAR AND MOLECULAR-BASIS OF CEREBRAL DYSGENESIS

Maldevelopment of the cerebral cortex, cortical dysgenesis (CD), may b e associated,vith epilepsy, mental retardation (MR), and focal or wide spread neurologic deficits. The histologic hallmark of CD is disrupted cytoarchitecture, including disorganized lamination, malpositioned ne urons with respect to their normal radial orientation, abnormal dendri tic arborization, and heterotopic neurons within the white matter. Sei zures in these patients are particularly difficult to control with con ventional anti-epileptic drugs (AEDs) and may require epilepsy surgery to remove these abnormal foci. Focal CD has been reported in up to 30 % of epilepsy surgery specimens and are believed to provide the centra l pathologic substrate responsible for seizures in these patients. How and why CD results in epileptiform activity is unknown. Advances in u nderstanding the pathogenesis of some types of CD have occurred recent ly with the cloning genes responsible for a few types of X-linked and autosomal CD. This review will outline the major subtypes of CD, the p athologic findings, and the molecular etiologies for a variety of CD. We will also address recent experimental advances in studying the path ogenesis of CD. (C) 1997 Wiley-Liss, Inc.