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Normal Function
The HARS2 gene provides instructions for making an enzyme called mitochondrial histidyl-tRNA synthetase. This enzyme is important in the production (synthesis) of proteins in cellular structures called mitochondria, the energy-producing centers in cells. While most protein synthesis occurs in the fluid surrounding the nucleus (cytoplasm), some proteins are synthesized in the mitochondria.
During protein synthesis, in either the mitochondria or the cytoplasm, a type of RNA called transfer RNA (tRNA) helps assemble protein building blocks (amino acids) into a chain that forms the protein. Each tRNA carries a specific amino acid to the growing chain. Enzymes called aminoacyl-tRNA synthetases, including mitochondrial histidyl-tRNA synthetase, attach a particular amino acid to a specific tRNA. Mitochondrial histidyl-tRNA synthetase attaches the amino acid histidine to the correct tRNA, which helps ensure that histidine is added at the proper place in the mitochondrial protein.
Health Conditions Related to Genetic Changes
Perrault syndrome
At least two mutations in the HARS2 gene have been found to cause Perrault syndrome. This rare condition is characterized by hearing loss in males and females with the disorder and abnormalities of the ovaries in affected females. The HARS2 gene mutations involved in Perrault syndrome reduce the activity of mitochondrial histidyl-tRNA synthetase. A shortage of functional mitochondrial histidyl-tRNA synthetase prevents the normal assembly of new proteins within mitochondria. Researchers speculate that impaired protein assembly disrupts mitochondrial energy production. However, it is unclear exactly how HARS2 gene mutations lead to hearing problems and ovarian abnormalities in affected individuals.
More About This Health ConditionOther Names for This Gene
- HARS-related
- HARSL
- HARSR
- hisRS
- histidine translase
- histidine tRNA ligase 2, mitochondrial (putative)
- histidine-tRNA ligase homolog
- histidyl-tRNA synthetase 2
- histidyl-tRNA synthetase 2, mitochondrial (putative)
- HO3
- PRLTS2
- probable histidine--tRNA ligase, mitochondrial
- probable histidine--tRNA ligase, mitochondrial isoform 2
- probable histidine--tRNA ligase, mitochondrial isoform 3
- probable histidyl-tRNA synthetase, mitochondrial
Additional Information & Resources
Tests Listed in the Genetic Testing Registry
Scientific Articles on PubMed
Catalog of Genes and Diseases from OMIM
References
- Konovalova S, Tyynismaa H. Mitochondrial aminoacyl-tRNA synthetases in human disease. Mol Genet Metab. 2013 Apr;108(4):206-11. doi: 10.1016/j.ymgme.2013.01.010. Epub 2013 Jan 26. Citation on PubMed
- Pierce SB, Chisholm KM, Lynch ED, Lee MK, Walsh T, Opitz JM, Li W, Klevit RE, King MC. Mutations in mitochondrial histidyl tRNA synthetase HARS2 cause ovarian dysgenesis and sensorineural hearing loss of Perrault syndrome. Proc Natl Acad Sci U S A. 2011 Apr 19;108(16):6543-8. doi: 10.1073/pnas.1103471108. Epub 2011 Apr 4. Citation on PubMed or Free article on PubMed Central
- Schwenzer H, Zoll J, Florentz C, Sissler M. Pathogenic implications of human mitochondrial aminoacyl-tRNA synthetases. Top Curr Chem. 2014;344:247-92. doi: 10.1007/128_2013_457. Citation on PubMed
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