Disorders of neuronal migration: sonographic features.

The cranial ultrasound features of two neonates with neuronal migration disorders are described. One infant had lissencephaly and the other polymicrogyria in conjunction with the Pena-Shokeir syndrome type 1. A third infant is described who was born extremely prematurely and with Down's syndrome, who had similar ultrasound features. By two weeks of age, however, the scan of this third infant had become normal, which illustrates the need for caution in diagnosing migrational disorders in very preterm babies and those with Down's syndrome. The disorders of neuronal migration are discussed.