CDKL5 and epilepsy: Interestingly, variants in the 5′UTR of CDKL5 have been identified in some patients affected by CDKL5 deficiency disorder (CDD), a severe loss-of-function monogenic neurodevelopmental syndrome characterized by cognitive disabilities, autistic-like features, refractory epilepsy, and hypotonia (Olson et al., 2019).