Of interest the previously reported truncating MT-ATP6 mutation m.9127-9128delAT; p.(Ile201Profs*2) was associated with myoclonic epilepsy, ataxia, and cerebellar atrophy, although the muscle biopsy did not reveal RRF.9 The phenotype was considered consistent with NARP, despite no evidence of neuropathy. Here, MT-ATP6 is linked to cerebellar ataxia.