MT-ND4 and Leber hereditary optic neuropathy: It is of note however, that an adeno-associated virus (AAV)-RPE65 therapy (voretigene neparvovec) has successfully progressed through to Phase III clinical trial (CHOP/Spark Therapeutics; www.sparktx.com), as has an AAV-ND4 therapy for Leber hereditary optic neuropathy (LHON) (51).