MT-ND4L and Leber hereditary optic neuropathy: Concerning the m.10680G>A/MT-ND4L variant, this has been found in 14 haplogroups and it has been previously reported as the only pathogenic change in three LHON families, arising as independent mutational events in haplogroups B4a1e, M13a1b and D6a1 [31,32].