RELN and polymicrogyria: These results suggest that heterozygous RELN variants are associated with a variety of cortical malformations, as diverse as pachygyria, a generalized transmantle migration abnormality, and polymicrogyria, which is still classified as a post-migrational disorder (51), in the absence of cerebellar hypoplasia, previously thought to be the hallmark of RELN-dependent autosomal recessive LIS.