SCO2 mutations are associated with infantile onset cardioencephalomyopathy with cerebral white matter and basal ganglia lesions, neurogenic muscular atrophy, and hypertrophic cardiomyopathy [45, 46]; DGUOK is also known as hepatocerebral syndrome (MTDPS3—mitochondrial DNA depletion syndrome 3) and characterised by SMA with infantile onset liver dysfunction, nystagmus, cerebral atrophy, and death from liver failure before age 12 months [47]. The gene discussed is DGUOK; the disease is pathologic nystagmus.