Figure 1.

Sequence characteristics and OSA-induced hypermethylation in the proximal promoter of the human eNOS gene. A, CpG dinucleotide positions and their relationship with the transcriptional machinery in the eNOS promoter. B, Methylation levels of seven CpG sites within the eNOS promoter among the three groups of children. Data are mean ± SE; *P < .001 vs OSAn or CO. Sequence details are derived from Karantzoulis-Fegaras et al²⁶ and Marsden et al.²⁷ Numbering is relative to the transcription start site (bent arrow). Underlined X = differentially methylated CpG; black X = nondifferentially methylated CpG; gray X = unexamined CpG. CO = control group; eNOS = endothelial nitric oxide synthase; OSAab = obstructive sleep apnea with delays in postocclusive hyperemic response; OSAn = obstructive sleep apnea with normal hyperemic response; PRD = positive regulatory domain.