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Late-onset Leber’s hereditary optic neuropathy: the role of environmental factors in hereditary diseases
  1. Nuno Moura-Coelho1,2,
  2. Rita Pinto Proença1,
  3. Joana Tavares Ferreira1,2 and
  4. João Paulo Cunha1,2
  1. 1 Ophthalmology, Centro Hospitalar Universitário Lisboa Central, Lisbon, Portugal
  2. 2 NOVA Medical School | Faculdade de Ciências Médicas - Universidade Nova de Lisboa (NMS|FCM-UNL), Lisbon, Portugal
  1. Correspondence to Dr Rita Pinto Proença, ritapintoproenca{at}


Leber’s hereditary optic neuropathy (LHON) is an optic neuropathy of mitochondrial inheritance, characterised by incomplete penetrance and variable expressivity. Typically, young male patients present with sequential, severe, rapidly progressive loss of central vision, with characteristic funduscopic findings. However, LHON may present at any age, in both genders, and fundus examination may be normal. Evidence has emerged to support the role of environmental factors in triggering LHON, by disrupting the normal mechanisms of mitochondrial function. We present two clinical cases of LHON of late onset, and provide a literature review on atypical cases of LHON and the role of environmental triggers.

  • neuroopthalmology
  • ophthalmology
  • visual pathway
  • genetics

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  • Contributors NM-C: planning, reporting, conception and design, acquisition of data, analysis and interpretation of data. RPP: conduct, analysis and interpretation of data. JTF: planning, reporting, conducting, conception and design, analysis and interpretation of data. JPC: planning, conducting, conception and design, analysis and interpretation of data.

  • 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 Not required.