MPO and obstructive sleep apnea syndrome: MPO encodes myeloperoxidase, which promotes atherosclerotic lesions by enhancing APOB oxidation in low-density lipoprotein (LDL)70 and is causally associated with cardiovascular events.71 A CpG located in PTCD2 has previously been associated with hypertension in patients with obstructive sleep apnea.72 Genetic variants of this gene have been associated with blood pressure.73 These differential methylated genes are enriched in various molecular and physiological pathways such as lipid metabolism and inflammatory diseases.