NDUFS4 and Leigh syndrome: This impressive outcome was linked to the improvement of the disease’s primary metabolic and biochemical indicators, such as EMA and thiosulfate levels in plasma and COX activity in tissues.435 Leigh syndrome is a progressive encephalopathy caused by defects in the NDUFS4, NDUFS3, and SurF1 genes and is the most common childhood mitochondrial disease.436 Leigh syndrome can result in a wide range of neurodegenerative disease phenotypes, including ataxia, dystonia, vision loss, and hearing loss.