MT-ND4 and Leber hereditary optic neuropathy: The potential of this gene therapy approach in rescuing the disease phenotype was first demonstrated in m.11778G>A LHON cybrids.84 The ability to rescue RGCs and improve visual function was subsequently confirmed in vivo by two independent research groups working on LHON rodent models expressing mutated ND4 (m.11778G>A) complex I subunits.85, 86 These groundbreaking experiments are paving the way for more advanced studies involving primates and ultimately patients with LHON (http://www.gensight-biologics.com/, accessed on 8 December 2013).