Table 2.

Human diseases associated with inactivation of enzymes that modify RNA nucleobases.

RNA methylation	Type of RNA	Methyltransferase gene	Human disease
m5C	25 rRNA	nsun1	Cri-du-chat syndrome [27]
	tRNA, mRNA	nsun2	Autosomal recessive intellectual disability [15,22,28]
			Dubowitz-like syndrome [23]
	mt tRNA	nsun3	Cardiomyopathy [51]
			Respiratory chain deficiency [51]
	tRNA	dnmt2	Cancer [19,50]
m1A	mt tRNA	trmt61B	Alzheimer’s disease [26]
	mt 16S rRNA		ER-negative breast cancer [17]
m6A	mRNA	mettl3	Colon cancer [19]
		mettl14	Endometrial cancer [16,19]
m1G	tRNA	trmt10A	Young onset diabetes [20,21]
			Microcephaly [20,21]
			Epilepsy [21]
			Intellectual disability [20,21]
m2,2G	tRNA	trmt1	Autosomal recessive Intellectual disability [29,60]