CDKL5 and craniodiaphyseal dysplasia: In this line, reduced dendritic arborization of cortical and hippocampal neurons and abnormal morphology and density of dendritic spines have been identified both in mice lacking Cdkl5 (Cdkl5‐KO) and in induced‐pluripotent stem cells (iPSCs)‐derived neurons from CDD patients.8