In MFN2, known as CMT2A and HMSN6A, phenotypes may cause optic atrophy, and in GDAP1, they may cause vocal cord paresis [2] so the spectrum of CMT has considerably broadened and multisystem involvement is frequently observed similar to other disorders caused by mutations in mitochondrial DNA (mtDNA) or mitochondria-related nuclear genes. The gene discussed is MFN2; the disease is hereditary optic atrophy.