MT-TD: MT-TD is a mitochondrial gene that codes for the tRNA for aspartic acid. It has been found to have two ancient mutations [PMC7514063]. In addition to its coding function, MT-TD has been identified as one of the top 10 noncoding regulators for ulncRNAs [PMC9127114]. MT-TD is one of several mitochondrial genes that have been implicated in various diseases, including multiple sclerosis [PMC7611844]. It is also part of a group of genes that are downregulated in grade 3 tumors [PMC9777612]. MT-TD is located on the H-strand of the mitochondrial genome, along with several other tRNA genes [PMC9657367]. Modifications have been identified at specific positions within MT-TD, including m1A at position 9 and Ψ modifications at positions 27 and 28 [PMC9308231]. The precursor RNA for MT-TD has been found to be processed in the absence of RNase P, resulting in a predominant processing intermediate that includes mt-Co1 and MT-TD [PMC5435911]. PCR amplification has been used to study specific regions within the mitochondrial genome, including MT-TD [PMC3812239]. Hypomethylation of mtDNA genes such as MT-TA, MT-TN, and MT-TC has been associated with hypermethylation of MAT and DNMT in nDNA [PMC5645762]. In multiple sclerosis, two novel mtSNV associations have been identified with m.7559A>G in MT-TD and rs2853826/m.10398A>G [PMC7611844]. Hypomethylation has also been observed in genes involved in protein synthesis during translation such as MT-TC and mitochondrially encoded tRNA serine 1 (MT-TS1), as well as cytochrome c oxidase genes (MT-CO1 and MT-CO2) [PMC5645762].