In fact, an expanding number of degenerative disorders have been associated with mutations in the genes encoding MFN2 and OPA1, including the rare Charcot-Marie-Tooth disease type 2A and autosomal dominant optic atrophy, and they also play a significant role in the molecular and cellular pathogenesis of more common neurodegenerative diseases, including Alzheimer’s and Parkinson’s diseases [44–45]. The gene discussed is MFN2; the disease is Parkinson disease.