Mental retardation, spasmodic seizures, dorsal vertebral defects, characteristic EEG findings, malformed or absent corpus callosum, Òbat-wingÓ 3rd and 4th ventricles, abnormal corneas and retina, and microphthalmos. In males, condition is lethal in utero; in females, it usually manifests itself in the first few months of life but occasionally develops as late as adolescence.