Mice deficient in Mfn1, Mfn2, and OPA1 are all embryonic lethal [47] and in humans, mutations in OPA1 are linked to hereditary blindness, and Mfn2 mutations are known to cause Charcot-Marie-Tooth disease [47–49]. The gene discussed is MFN2; the disease is Charcot-Marie-Tooth disease.