MT-ND4 and Leber hereditary optic neuropathy: More recently, in murine LHON models (Qi et al., 2007; Ellouze et al., 2008; Yu et al., 2012a,b), intraocular injection of human nuclear ND4 gene constructs expressed by AAV has been shown to be safe (Ellouze et al., 2008; Yu et al., 2012a); non-mutagenic to host mtDNA (Yu et al., 2013); prevent retinal ganglion cells loss; and improve optic atrophy and vision (Ellouze et al., 2008; Yu et al., 2012a).