Knockout mice of Mfn1, Mfn2, and OPA1 are all embryonic lethal [40] and mutations in OPA1 in humans are associated with hereditary blindness, while Mfn2 mutations are the cause of Charcot-Marie-Tooth disease [27, 40, 41]. The gene discussed is MFN1; the disease is Charcot-Marie-Tooth disease.