Leber hereditary optic neuropathy (LHON) results from point mutations in mitochondrial DNA (mtDNA) present in all cells but is only manifested in retinal ganglion cells (RGCs). Given that RGCs use superoxide for intracellular signaling after axotomy, and that LHON mutations increase superoxide levels in non-RGC transmitochondrial cybrids, I hypothesized that RGCs regulate superoxide levels differently than other neuronal cells.
