POLG mutations associated with remitting/relapsing neurological events.

Recent experimental data underline the relationship between mitochondria and immune function. Clinical reports of patients presenting with mitochondrial dysfunction associated with dysimmune responses in the central nervous system reinforce this new concept. We describe the first case of a woman presenting with symptoms related to a novel compound heterozygous mutation of the mitochondrial polymerase γ (POLG) gene, associated with neurological events suggestive of a demyelinating process. Clinical examination revealed bilateral ptosis, progressive external ophthalmoplegia and axonal sensitive polyneuropathy suggestive of a mitochondrial disease. In line with this, muscle biopsy showed ragged red fibers, and sequencing of POLG revealed two heterozygous mutations. In addition, the patient exhibited relapsing neurological symptoms, and cerebral and spinal MRI mimicking multiple sclerosis. This patient stresses the relationship between mitochondrial dysfunction and inflammation. Recent studies suggest that targeting mitochondrial dysfunction could provide benefits in treating some inflammatory diseases.