Mitochondrial Genome Profile in Demyelinating Diseases

Multiple sclerosis and neuromyelitis optica are chronic inflammatory diseases of the central nervous system. These pathologies share clinical similarities with Leber hereditary optic neuropathy, which is primarily due to mutations of mitochondrial DNA. Mitochondrial genetic variations may influence susceptibility to develop multiple sclerosis and neuromyelitis optica. In order to explore the possible correlation between mitochondrial DNA specific patterns and demyelinating diseases involving central nervous system, mitochondrial DNA from 13 patients with relapsing-remitting multiple sclerosis, 4 patients with neuromyelitis optica, 1 patient with myelitis, 2 patient with optic neuritis, and 7 healthy controls were analyzed by sequencing the full length 16 Kbs of the mitochondrial DNA genome. Common variants presence in healthy controls and patients showing no clinical impact on diseases development were not further explored. Analyzing 414 patient specific variants, six nonsense mutations, causing early stop-codon formation, and nine previously described variants, associated with demyelinating/degenerative disease of central nervous system were identified. Some of these variants are linked to disease development through known and previously described mechanisms. We report for the first time other truncating mutations leading to incomplete proteins involved in Oxidative Phosporilation complexes and we speculate their role in demyelinating diseases development.