POLG and Alpers syndrome: Clinically, POLG mutations are associated with a wide range of overlapping phenotypes that vary depending on age from devastating infantile disorders such as Alpers syndrome (OMIM # 203700) and myocerebrohepatopathy spectrum; to juvenile and adult onset myoclonic epilepsy, myopathy and sensory ataxia (MEMSA), and ataxia neuropathy spectrum (ANS); and to late onset myopathies with progressive external ophthalmoplegia (PEO) [5,6].