Mitochondrial glutamyl-tRNA synthetase is a major component of protein biosynthesis that loads tRNAs with cognate amino acids. Mutations in the gene encoding this enzyme have been associated with a variety of disorders related to oxidative phosphorylation. Here, we present a case of leukoencephalopathy with thalamus and brainstem involvement and high lactate (LTBL) presenting a biphasic clinical course characterized by delayed psychomotor development and seizure.. High-throughput sequencing revealed a novel compound heterozygous mutation in mitochondrial glutamyl-tRNA synthetase 2 (EARS2), which appears to be causative of disease symptoms. (C) 2016 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.