MT-ATP6 and Leigh syndrome: Variants in MT-ATP6 are a well-known cause for maternally inherited mitochondrial disorders associated with a continuous spectrum of clinical phenotypes [2,3], e.g., clinically grouped into Leigh syndrome (LS) [4,5], neuropathy, ataxia and retinitis pigmentosa syndrome (NARP) [6,7], Charcot–Marie–Tooth (CMT) disease-like pure peripheral neuropathy [8], and spinocerebellar ataxia (SCA) with upper motor neuron signs [9,10].