Lissencephaly ('smooth brain') is a severe disorder of brain development in which neuronal migration is impaired, leading to a thickened cerebral cortex in which the normally folded contour is simplified and smooth. Lissencephaly-2 (LIS2) is associated with severe abnormalities of the cerebellum and hippocampus (summary by Hong et al., 2000). For a general phenotypic description and a discussion of genetic heterogeneity of lissencephaly, see LIS1 (607432).

Complex cortical dysplasia with other brain malformations-10 (CDCBM10) is an autosomal recessive neurodevelopmental disorder characterized by severely impaired global development associated with abnormalities on brain imaging, including lissencephaly, cortical dysplasia, subcortical heterotopia, and paucity of white matter. The disorder results from defective neuronal migration during brain development. Affected individuals often develop seizures, are unable to walk, and do not acquire language (summary by Lee et al., 2019). For a discussion of genetic heterogeneity of CDCBM, see CDCBM1 (614039).