Since oxidative stress is a characteristic trait of the CDD phenotype, we evaluated the effect of UBQ supplementation on oxidative stress in a human neuronal cell model of CDKL5 deficiency, the CDKL5 knockout (KO) SH-SY5Y neuroblastoma cell line (SH-CDKL5-KO [18]). This evidence concerns the gene CDKL5 and craniodiaphyseal dysplasia.