MT-ATP6 and glycogen storage disease VI: Established syndromes of MT‐ATP6–related mitochondrial disease include Leigh syndrome (LS),1 and the syndrome of neuropathy, ataxia, and retinitis pigmentosa (NARP).2 Other presentations associated with MT‐ATP6 mutations include a Charcot‐Marie‐Tooth (CMT) disease–like pure peripheral neuropathy3 and spinocerebellar ataxia (SCA) with upper motor neuron signs.4 However, the relative frequency of various presentations and features most suggestive of MT‐ATP6 disease remains unclear.