Mean DNA methylation levels over − 32, − 25, − 18, − 11 and − 1 CpG sites of the ATG5 gene were increased in SDB patients with morning headache versus those without morning headache (11.36 ± 7.88 versus 7.77 ± 6.11%, adjusted p = 0.013, Fig. 3F). This evidence concerns the gene ATG5 and sleep apnea syndrome.