Yet, abnormalities in these genes predominantly affect retinal ganglion cells and present in the form of blinding disorders that have little or no overt extra-ophthalmic pathology (e.g., mitochondrial optic neuropathies such as autosomal dominant optic atrophy (ADOA) caused by mutations in OPA1 and Leber’s hereditary optic neuropathy (LHON) caused by mtDNA mutations affecting mitochondrial Complex I [7]). Here, OPA1 is linked to autosomal dominant optic atrophy.