Mutations in genes encoding components of the mitochondrial fission/fusion machineries have been linked to human neurodegenerative diseases: Mfn2 in Charcot-Marie-Tooth neuropathy type 2A (CMT2A) [177], OPA1 in autosomal dominant optic atrophy (ADOA) [125, 178], GDAP1 in Charcot-Marie-Tooth neuropathy type 4A (CMT4A) [179, 180] and Drp1 in abnormal brain development, optic atrophy and neonatal lethality [17]. The gene discussed is OPA1; the disease is Charcot-Marie-Tooth disease type 4A.