MT-ND6 and Leber hereditary optic neuropathy: Genes MT-ND1 and MT-ND6 are reported as hotspots for LHON-causative mutations (Reynier et al. 1999; Valentino et al. 2004; Fraser et al. 2010), which harbor ‘14 Top primary mutations’ (Wallace et al. 1988; Howell et al. 1991; Johns et al. 1992; Brown et al. 1995; Chinnery et al. 2001; Kim et al. 2002; Gropman et al. 2004; Achilli et al. 2012) annotated in Mitomap (Lott et al. 2013).