CDKL5 and craniodiaphyseal dysplasia: We generated bona fide human iPSC-derived cortical neurons by dual-SMAD inhibition [29–32], which we previously demonstrated recapitulate many features of CDD, including impaired neurite outgrowth and reduced phosphorylation of EB2 [28], which is a direct phosphorylation target of CDKL5 [8, 9, 16].