By using a patient-derived male iPSC cell line carrying the CDKL5 variant c.175C>T (resulting in p.Arg59*, where the asterisk (*) denotes a premature stop codon, according to HGVS nomenclature) [43] alongside CRISPR-Cas9 gene-edited isogenic controls (genetically matched), the authors generated human iPSC-derived cortical cells, which recapitulate features of CDD, such as impaired neurite outgrowth and reduced phosphorylation of EB2, a known direct phosphorylation substrate for CDKL5 [42]. The gene discussed is CDKL5; the disease is craniodiaphyseal dysplasia.