Are there any therapies that can slow the progression of EARS2‑related leukoencephalopathy?

Management is mainly supportive: physical, occupational, and speech therapy to maintain function; antiepileptic drugs for seizures; and a mitochondrial “cocktail” (coenzyme Q10, riboflavin, thiamine, and L‑carnitine) may provide modest benefit, though evidence is limited.

What is the recurrence risk for future children and should we consider genetic testing?

EARS2 mutations are inherited in an autosomal recessive pattern, giving a 25 % chance of an affected child for each pregnancy if both parents are carriers. Carrier testing for the parents and prenatal or pre‑implantation genetic testing can inform future family planning.

My child was diagnosed with LTBL due to an EARS2 mutation. What neurological symptoms should we monitor as the disease progresses?

Watch for worsening motor delays, difficulty walking or maintaining balance, frequent falls, spasticity, speech regression, and new seizures. Changes in cognition, such as memory problems or reduced attention, also warrant prompt evaluation.

How is the high lactate level measured and does it guide treatment?

Lactate is measured in blood and sometimes cerebrospinal fluid using a lactate analyzer. Persistently elevated levels indicate mitochondrial dysfunction but do not change specific therapy; they help confirm the diagnosis and monitor disease activity.

EARS2 gene

EARS2 encodes mitochondrial glutamyl‑tRNA synthetase, essential for protein synthesis in mitochondria; mutations are linked to leukoencephalopathy with thalamus and brainstem involvement and high lactate (LTBL) and Leigh syndrome.

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.

Health Conditions Related to Genetic Changes

Leukoencephalopathy with thalamus and brainstem involvement and high lactate (LTBL)

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.

Leigh syndrome

MedlinePlus Genetics provides information about Leigh syndrome

Other Names for This Gene

COXPD12
gluRS
glutamate tRNA ligase 2, mitochondrial
glutamate--tRNA ligase
KIAA1970
MSE1

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Tests of EARS2

Scientific Articles on PubMed

PubMed

Catalog of Genes and Diseases from OMIM

GLUTAMYL‑tRNA SYNTHETASE 2, MITOCHONDRIAL; EARS2

Gene and Variant Databases

NCBI Gene
ClinVar

References

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 Leukoencephalopathy with Thalamus and Brainstem Involvement and High Lactate (LTBL) in a Patient Harboring a Novel EARS2 Mutation. JIMD Rep. 2015;23:85-9. doi:10.1007/8904_2015_434. Epub 2015 Apr 9. Citation on PubMed or Free article on PubMed Central
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 fatal neonatal 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. Epub 2016 Jan 16. Citation on PubMed
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. Epub 2015 Nov 30. Citation on PubMed
Steenweg ME, Ghezzi D, Haack T, Abbink TE, Martinelli D, van Berkel CG, Bley A, Diogo L, Grillo E, Te Water Naude 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(Pt 5):1387-94. doi: 10.1093/brain/aws070. Epub 2012 Apr 4. Citation on PubMed
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 a Homozygous EARS2 Mutation. J Child Neurol. 2016 Jun;31(7):938-41. doi:10.1177/0883073816630087. Epub 2016 Feb 18. Citation on PubMed

Genomic Location

The EARS2 gene is found on chromosome 16.

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