First, degeneration of the optic nerve, leading to the loss of vision, seems to appear in an apoptotic way (swelling of the mitochondria at the optic nerve head, release of cytochrome C).28 Second, studies of cybrids with the m.11778G>A and m.3460G>A mitochondrial DNA mutations show a higher sensitivity for Fas-induced apoptosis, in comparison to analogous cells without LHON mutation.29 That phenomenon can be explained by alterations in complex I. It is known that complex I and ubiquinone analogs play a regulatory role in the opening of the mitochondrial transition pore. The gene discussed is CYCS; the disease is Leber hereditary optic neuropathy.