Transfer RNA, Mitochondrial, Aspartic Acid

Alternative Names

MTTD
tRNA-asp, Mitochondrial

Associated Diseases

ATP Synthase 8; Multiple Endocrine Neoplasia, Type IIA; Multiple Endocrine Neoplasia, Type IIB

OMIM Number

Description

Mitochondrial DNA (mtDNA) is multicopy and maternally inherited. mtDNA is 16,500 basepairs long and codes for 37 genes including 13 polypeptides, 22 transfer RNAs (tRNA), and two ribosomal RNAs (rRNA). Transfer RNAs (tRNAs) are key molecules in protein biosynthesis in all living organisms. They have specific structural properties allowing interactions with several partners such as their cognate aminoacyl-tRNA synthetases (aaRSs), elongation factor, mRNA or ribosome.

Molecular Genetics

The MT-TD gene spans 68 bases within the mitochondrial DNA between 7,518 to 7,585 base pairs. Mutations in the MT-TD gene have been associated with mitochondrial disorders. To date, only three MTTD gene mutations have been identified with clear evidence of pathogenicity including m.7526A > G transition associated with exercise intolerance, m.7543A > G mutation leading to myoclonic seizures, developmental delay, and severe behavioral problems and m.7554G > A transition associated with a multisystemic disease presentation comprising myopathy, ataxia, nystagmus, and migraine.

Epidemiology in the Arab World

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Saudi Arabia

Other Reports

Saudi Arabia

Abu-Amero et al. (2006) sequenced the entire coding region of mitochondrial DNA for 26 MTC patients and 119 normal population controls. Of the MTC patients 13 were sporadic, nine had MEN 2A, one had MEN 2B, and three had FMTC. In 20 MTC samples, 41 nonsynonymous mutations were detected; nine were from sporadic MTC and 11 were from familial MTC and MEN2. Also, 15 synonymous mtDNA sequence variants were found in MTC samples, seven of them were novel. Twenty seven mutations were transversions; 22 nonsynonymous and six synonymous. These transversion variants were only detected in FMTC/MEN2 while transition variants were mainly in sporadic MTC. One nonsynonymous variant was identified in the tRNA-asp gene, a G>A transition mutation with unknown pathogenicity. Like many mutations described in the study, this mutations was not present in the normal controls suggesting that it may also be involved in MTC tumorigensis and progression.

Contributors

Nada Assaf: 14.04.2015

Edit History

Pratibha Nair: 01.10.2015

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