Phenylalanyl-tRNA synthetase, mitochondrial (FARS2) is an enzyme that in humans is encoded by the FARS2 gene. This protein encoded by FARS2 localizes to the mitochondrion and plays a role in mitochondrial protein translation. Mutations in this gene have been associated with combined oxidative phosphorylation deficiency 14, also known as Alpers encephalopathy, as well as spastic paraplegia 77 and infantile-onset epilepsy and cytochrome c oxidase deficiency.