A new POLG1 mutation with peo and severe axonal and demyelinating sensory-motor neuropathy.

Progressive external ophthalmoplegia (PEO) is a mitochondrial disorder associated with defective enzymatic activities of oxidative phosphorylation (OXPHOS), depletion of mitochondrial DNA (mtDNA) and/or accumulation of mtDNA mutations and deletions. Recent positional cloning studies have linked the disease to four different chromosomal loci. Mutations in POLG1 are a frequent cause of this disorder.