Table 1.

List of DR-related genes and their aberrant methylation status

Pathogenesis	Key genes	DNA methylation status	References
Oxidative stress	PLOG1	Hypermethylation	Mishra et al. [45]
	D-loop	Hypermethylation	Mishra et al. [45]
	MLH1	Hypermethylation	Mohammad et al. [52]
	MMP-9	Hypomethylation	Zhou et al. [54]
	RAC1	Hypomethylation	Duraisamy et al. [18]
	PPARα	Hypermethylation	Zhu et al. [17]
	MnSOD/SOD2	Hypermethylation	Duraisamy et al. [49]
Inflammation	NLRP3, TGFβ1, MCP-1, TNFSF2	Hypomethylation	Chen et al. [62]
	MALAT1	Hypomethylation	Zhu et al. [17]
Neovascularization	MEG3	Hypermethylation	He et al. [80]
	ETS1, HES5, PRDM16	Unknown	Berdasco et al. [20]
Others	MTHFR	Hypermethylation	Dos Santos Nunes et al. [96]
			Santana Bezerra et al. [98]
	SIRT1	Hypermethylation	Mishra et al. [101]
			Chen et al. [102]

POLG1, polymerase gamma 1; D-loop, displacement loop; MLH1, MutL homolog 1; MMP-9, matrix metalloproteinase-9; RAC1, Ras-related C3 botulinum toxin substrate 1; PPARα, peroxisome proliferator-activated receptor alpha; MnSOD, mitochondrial superoxide dismutase; NLRP3, NOD-like receptor 3; TGFβ1, transforming growth factor beta-1; MCP-1, monocyte chemoattractant protein-1; TNFSF2, tumor necrosis factor ligand superfamily member 2; MALAT1, metastasis-associated lung adenocarcinoma transcript 1; MEG3, maternally expressed gene 3; MTHFR, methylenetetrahydrofolate reductase; SIRT1, sirtuin 1