To better refine the efficiency of allotropic expression strategy in the context of RGCs, detailing the mitochondrial import of wild-type ND4 protein, its competition with the endogenously expressed mutant ND4, and finally the dynamics of complex I assembly of either one or the other ND4 subunits, may greatly benefit of 3D organoid modeling of LHON. This evidence concerns the gene MT-ND4 and Leber hereditary optic neuropathy.