PCDH19 and Miller-Dieker lissencephaly syndrome: We speculate that mosaic expression of PCDH19 may alter the radial glia cell division through the interaction with NCAD, as the NCAD/β-catenin signaling pathway has been previously implicated in the expansion defects of radial glia cells in Miller-Dieker Syndrome (MDS) (Iefremova et al., 2017) and later synaptic development in Pcdh19 heterozygous mice (Hoshina et al., 2021).