This study aimed to explore the role of additional mitochondrial DNA (mtDNA) variants in the development of Leber hereditary optic neuropathy (LHON) by screening the entire mitochondrial genome in individuals who had previously tested negative for the three common mtDNA variants: m.3460G > A (MT-ND1), m.11778G > A (MT-ND4), and m.14484 T > C (MT-ND6), by conventional Sanger sequencing. Here, MT-ND6 is linked to Leber hereditary optic neuropathy.