Since OPA1 was first linked to dominant optic atrophy, a disease that affects retinal ganglion cells and the optic nerve, several other diseases related to the nervous system, namely spastic paraplegia, multiple sclerosis-like syndrome, parkinsonism, and dementia, have been associated with OPA1 gene mutations (for review, see [207]). Here, OPA1 is linked to Parkinsonism.