Rapamycin (8 mg/kg i.p. starting 10 days after birth) markedly ameliorated the clinical phenotype and prolonged the median lifespan (from 50 to 110 days) of a knockout mouse for Ndufs4 (Ndufs4 KO), encoding the 18 kDa subunit of respiratory complex I, characterized by rapidly progressive encephalopathy resembling LS [9]. This evidence concerns the gene NDUFS4 and Leigh syndrome.