Mfn2K357T/K357T mice displayed a severe phenotype with early postnatal lethality, while Mfn2+/K357T mice manifested mild manifestations of CMT2A disease, including abnormal mitochondrial clustering, especially in their sciatic nerves, and delayed microgliosis. The gene discussed is MFN2; the disease is Charcot-Marie-Tooth disease type 2A1.