In particular, we demonstrated that Cdkl5 -/Y adult mice showed more frequent sleep apneas compared to Cdkl5 +/Y [30] mice, and that, at least in adult (4- to 6- month-old) mice, sleep apneas are a core feature of CDKL5 disorder and a respiratory biomarker of CDKL5 deficiency. This evidence concerns the gene CDKL5 and sleep apnea syndrome.