MT-ATP6 and Global developmental delay: <h4>Purpose</h4>To describe a case with Leber's hereditary optic neuropathy (LHON) like optic atrophy in the presence of <i>MT-ATP6</i> gene variant m.8969G > A.<h4>Observations</h4>A 20-year-old patient with a history of mild developmental delay, mild cognitive impairment, and positional tremor presented with subacute painless visual loss over a few weeks.