RARS2 and Epileptic encephalopathy: PCH6 is associated with genetic alterations of the mitochondrial arginine tRNA synthetase gene, RARS2, and it is characterized by a phenotype of severe epilepsy with early occurrence of first episodes, epileptic encephalopathy, widely distributed brain atrophy, especially in pontocerebellar regions, lactic acidosis, and mitochondrial respiratory chain defects [30].