MFN2 and autosomal dominant optic atrophy: Pathological mutations in Mfn2 and Opa1 impede mitochondrial fusion, where Mfn2 causes the axonal CMT disease type 2A, which is characterized by the degeneration of retinal ganglion cells and the optic nerve, and Opa1 causes autosomal dominant optic atrophy, with the degeneration of peripheral sensory and motor neurons (Westermann, 2010; Burté et al., 2015).