MT-ATP6 and cerebellar ataxia: For instance, the heteroplasmic m.8561C>G or m.8561C>T mutations in the overlapping region of MT-ATP6 and MT-ATP8 in adult and childhood caused severe neurological signs, presenting with cerebellar ataxia, psychomotor delay, peripheral neuropathy, and microcephaly (Kytövuori et al., 2016; Fragaki et al., 2019).