Table 1

Clinical phenotypes of POLG mutations

InheritanceNameOther namesClinical featuresTypical age at onset (years)
Autosomal recessiveAlpers–Huttenlocher syndrome Liver dysfunction0–10
Occipital epilepsy
Encephalopathy
Syndrome of sensory ataxic neuropathy with ophthalmoparesis (SANDO)Autosomal recessive progressive external ophthalmoplegia (arPEO)Progressive external ophthalmoplegia40–70
Axonal sensorimotor neuropathy
Myopathy
Mitochondrial recessive ataxia syndrome (MIRAS)Myoclonus, epilepsy, myopathy and sensory ataxia (MEMSA)Occipital epilepsy0–30
Myoclonus
Ataxia
Ataxia neuropathy spectrum syndrome (ANS)Ataxia
Axonal sensorimotor neuropathy
Myocerebrohepatopathy syndrome (MCHS)Encephalopathy
Myopathy
Liver dysfunction
Autosomal dominantAutosomal dominant progressive external ophthalmoplegia (adPEO) Progressive external ophthalmoplegia40–70
Parkinsonism
Premature ovarian failure