Table 1.

Neurological diseases and implications of DNA methylation.

Disease	Patterns	Main Factors	References
Alzheimer’s disease	CpG methylation	Methylated interleukin-6	[97]
	CpG methylation	Hypermethylated TXBA2R, SORBS3, and SPTBN4	[102]
	CpG/non-CpG methylation	Hypermethylated mitochondrial DNA	[103]
Rett syndrome	MeCp2 mutation	Mutations in MeCP2 target genes (Bdnf, Fkbp5, Dlx5, Dlx6, UBE3A, and Sgk)	[111,112,113,114,115]
	Non-CpG methylation	Binding of MeCP2 to methylated non-CpG sites	[117]
	MeCP2-5hmC interaction	Inhibition of conversion from 5mC to 5hmC	[89]
Fragile X syndrome	Histone deacetylation and DNA hypermethylation	Abnormal expansion of CGG repeat in 5’ UTR of FMR1 gene	[121]
Parkinson’s disease	CpG methylation	Hypomethylation of SNCA	[130]
	CpG methylation	Hypomethylation of TNF-αpromoter	[134]
	CpG/non-CpG methylation	Hypomethylation of mitochondrial DNA	[102]
Huntington’s disease	CpG methylation	Neurotrophic factors (Bdnf and A2A)	[139]
	CpG methylation	Interaction of mutant Htt with MeCP2	[143]
	5hmC	Regulation of Adora2a expression by 5hmC levels	[139]
Amyotrophic lateral sclerosis	CpG methylation	5mC accumulation in motor neurons	[150]
	DMNT1 transcription	Increased levels of Dnmt3a lead to apoptosis	[150]
	Genetic mutation	Gene mutations in SOD1, C9orf72, TARDBP, and FUS genes	[152]