EARS2 and Encephalopathy: Different forms of severe encephalopathies depend on mutated mitochondrial tRNA, as in the case of the mitochondrial tRNA-Lys (MERRF), tRNA-Leu (MELAS) or tRNA-Phe, and on an impaired tRNA synthetase (as for EARS2 deficiency, which depends on the mutated glutamyl-tRNA synthetase) [19,24,25,181,182].