Despite their ubiquitous expression, mt-ARS deficiencies predominantly affect the CNS, presenting as leukodystrophies (AARS2, DARS2, EARS2, and occasionally LARS2), Leigh syndrome (MARS2, PARS2, NARS2, IARS2), sensorineural hearing loss with ovarian failure (LARS2, HARS2), epilepsy (VARS2, FARS2, RARS2, CARS2), and extrapyramidal syndromes (WARS2, CARS2) (2, 16, 17). The gene discussed is NARS2; the disease is leukodystrophy.