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Late-onset presentation of POLG1-associated mitochondrial disease
  1. Bruna Meira1,
  2. Rafael Roque2,
  3. Miguel Pinto1 and
  4. André Caetano1
  1. 1 Neurology Department, Centro Hospitalar de Lisboa Ocidental EPE, Lisboa, Portugal
  2. 2 Neuropathology Unit - Neurology Department, Centro Hospitalar Lisboa Norte EPE, Lisboa, Portugal
  1. Correspondence to Dr Bruna Meira, bmeira.rmm{at}


Mutations in the nuclear POLG1 gene compromise the integrity of mitochondrial DNA and show great allelic and clinical heterogeneity. Among adult POLG1-associated mitochondrial disease, the main clinical feature is chronic progressive external ophthalmoplegia. Other related clinical manifestations are sensory or cerebellar ataxia, peripheral neuropathy, myopathy or extrapyramidal symptoms. We report the case of a 72-year-old man who presented with a late onset sensory neuronopathy, chronic progressive external ophthalmoplegia, gait ataxia and parkinsonism. Genetic studies showed a compound heterozygosity of known pathogenic mutations in the POLG1 gene (variant T252I/P587 L in cis configuration in allele 1 and variant R807C in allele 2). Late life presentation highlights that mitochondrial disorders should be considered regardless of age of onset of symptoms.

  • neuromuscular disease
  • muscle disease
  • neuro genetics
  • neuroopthalmology
  • parkinson’s disease

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  • Contributors All authors have contributed to the manuscript. BM: planning, drafting and revising of the manuscript and image edition. RR: interpretation and reporting muscle biopsy, revising of the manuscript. MP and AC: revising of the manuscript for intellectual content.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Patient consent for publication Obtained.