Mutations in the POLG gene are associated with various clinical syndromes: autosomal recessive Alpers–Huttenlocher syndrome in small children, ataxia-neuropathy spectrum in teenagers and young adults, and adult PEO-related disorder which beside ocular muscles may affect skeletal muscles as well as the brain, heart, and peripheral nerves [25]. This evidence concerns the gene POLG and cerebellar ataxia.