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    EARS2 Gene

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    Submitted by: Vivi Li
    (This entry belongs to Entry Collection "MedlinePlus ")

    Definition

    Glutamyl-tRNA Synthetase 2, Mitochondrial

    1. Normal Function

    The EARS2 gene provides instructions for making an enzyme called mitochondrial glutamyl-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 cell 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 called 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 glutamyl-tRNA synthetase, attach a particular amino acid to a specific tRNA. Mitochondrial glutamyl-tRNA synthetase attaches the amino acid glutamate to the correct tRNA, which helps ensure that glutamate is added at the proper place in the mitochondrial protein.

    2. Health Conditions Related to Genetic Changes

    2.1 Leukoencephalopathy with Thalamus and Brainstem Involvement and High Lactate

    At least 23 mutations in the EARS2 gene have been found in individuals with leukoencephalopathy with thalamus and brainstem involvement and high lactate (LTBL), a condition characterized by abnormalities in certain brain regions, including the thalamus and the brainstem (the part of the brain that connects to the spinal cord), and a high level of a substance called lactate in the brain and elsewhere in the body. Affected individuals typically have problems with thinking and motor abilities and with controlling muscle function.

    The EARS2 gene mutations involved in LTBL likely reduce the amount of mitochondrial glutamyl-tRNA synthetase. A shortage of this protein is thought to prevent the normal assembly of new proteins within mitochondria. Researchers speculate that impaired protein assembly disrupts mitochondrial energy production. However, it is unclear exactly how EARS2 gene mutations lead to the features of LTBL.

    2.2 Leigh Syndrome

    3. Other Names for This Gene

    • COXPD12

    • gluRS

    • glutamate tRNA ligase 2, mitochondrial

    • glutamate--tRNA ligase

    • KIAA1970

    • MSE1

    This entry is adapted from https://medlineplus.gov/genetics/gene/ears2

    References

    1. Biancheri R, Lamantea E, Severino M, Diodato D, Pedemonte M, Cassandrini D,Ploederl A, Trucco F, Fiorillo C, Minetti C, Santorelli FM, Zeviani M, Bruno C.Expanding the Clinical and Magnetic Resonance Spectrum of Leukoencephalopathywith Thalamus and Brainstem Involvement and High Lactate (LTBL) in a PatientHarboring a Novel EARS2 Mutation. JIMD Rep. 2015;23:85-9. doi:10.1007/8904_2015_434.
    2. Danhauser K, Haack TB, Alhaddad B, Melcher M, Seibt A, Strom TM, Meitinger T, Klee D, Mayatepek E, Prokisch H, Distelmaier F. EARS2 mutations cause fatalneonatal lactic acidosis, recurrent hypoglycemia and agenesis of corpus callosum.Metab Brain Dis. 2016 Jun;31(3):717-21. doi: 10.1007/s11011-016-9793-2.
    3. Kevelam SH, Klouwer FC, Fock JM, Salomons GS, Bugiani M, van der Knaap MS.Absent Thalami Caused by a Homozygous EARS2 Mutation: Expanding Disease Spectrum of LTBL. Neuropediatrics. 2016 Jan;47(1):64-7. doi: 10.1055/s-0035-1568987.
    4. Steenweg ME, Ghezzi D, Haack T, Abbink TE, Martinelli D, van Berkel CG, BleyA, Diogo L, Grillo E, Te Water Naudé J, Strom TM, Bertini E, Prokisch H, van der Knaap MS, Zeviani M. Leukoencephalopathy with thalamus and brainstem involvement and high lactate 'LTBL' caused by EARS2 mutations. Brain. 2012 May;135(Pt5):1387-94. doi: 10.1093/brain/aws070.
    5. Taskin BD, Karalok ZS, Gurkas E, Aydin K, Aydogmus U, Ceylaner S, Karaer K,Yilmaz C, Pearl PL. Early-Onset Mild Type Leukoencephalopathy Caused by aHomozygous EARS2 Mutation. J Child Neurol. 2016 Jun;31(7):938-41. doi:10.1177/0883073816630087.
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