POLG gene encodes the catalytic subunit of mitochondrial DNA polymerase, which is involved in the replication and repair of mitochondrial DNA.
Mutations in POLG gene are associated with several diseases, commonly known as POLG-related disorders. These disorders are characterized by neuronal and hepatic degeneration. Dominant mutations typically cause adult-onset myopathies and encephalopathies, whereas recessive mutations result in more severe disorders, such as progressive external ophthalmoplegia with mitochondrial DNA deletions (PEOA), sensory ataxic neuropathy dysarthria and ophthalmoparesis (SANDO), mitochondrial neurogastrointestinal encephalopathy syndrome (MNGIE), and Alpers-Huttenlocher syndrome.