Polymicrogyria

Polymicrogyria (also known as cobblestone lissencephaly) is a neurodevelopmental disorder with abnormal gyrification of the cerebral cortex: Instead of the few and large convolutions (gyri), multiple small convolutions occur, in the result of which the brain surface appears pebbled. Further diagnostic criteria include white matter reduction, ventricular enlargement, and hypoplasia of the brainstem and cerebellum.