Interestingly, both cdkl5−/− fish and Cdkl5R59X mice did not show significant differences in the overall severity and duration of seizures recorded (Yennawar et al., 2019), although it is not known whether seizure activity can change over time in CDD patients (Jakimiec et al., 2020). This evidence concerns the gene CDKL5 and craniodiaphyseal dysplasia.