Consistent with the data from human lissencephaly patients, knocking out the Cdk5 gene in pyramidal neurons of the developing ferret cerebral cortex by combining in utero electroporation and the CRISPR/Cas9 system attenuated cortical folding, suggesting that Cdk5 in pyramidal neurons is crucial for cortical folding (Shinmyo et al., 2017). Here, CDK5 is linked to lissencephaly spectrum disorders.