title: Orbicularis oculi: morphological changes mimicking mitochondrial cytopathy in a series of control normal muscles.
abstract: BACKGROUND
  Orbicularis oculi (OO) muscle has recently proposed as a suitable muscle for biopsy to diagnose mitochondrial cyopathy:
  
  
  METHODS
  Enzyme histochemical and immunohistochemical studies were performed on OO muscle obtained from 18 patients aged 37-87 years (median 64 years), 6 males, 12 females, who were undergoing routine upper blepharoplasty surgery.
  
  
  RESULTS
  We confirmed the marked type II fibre (fast myosin heavy chain) predominance (89%) but also noted a different proportion and distribution of mitochondria in these fibres with occasional pseudo-'ragged-red' fibres with prominent subsarcolemmal and cytoplasmic aggregation of mitochondria. Cytochrome oxidase-negative fibres and true 'ragged-red' fibres were found at all ages over 40 years at levels that approach those used for diagnosis of mitochondrial cytopathy in peripheral or limb skeletal muscles.
  
  
  CONCLUSIONS
  We would therefore urge caution in the use of OO as muscle biopsy for diagnosis of mitochondrial cytopathy and advise concomitant biopsy of limb skeletal muscle and/or supplementary genetic studies.
authors: Department of Anatomical Pathology, St Vincent's Hospital Melbourne, Fitzroy, VIC 3065, Australia. penny.mckelvie@svhm.org.au
authors: Penelope
authors: P
authors: McKelvie
authors: Khami
authors: K
authors: Satchi
authors: Alan A
authors: AA
authors: McNab
authors: Paul
authors: P
authors: Kennedy
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D019882:Blepharoplasty; D003576:Electron Transport Complex IV / Q000378:metabolism; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D008931:Mitochondria, Muscle / Q000201:enzymology / Q000473:pathology*; D017240:Mitochondrial Myopathies / Q000175:diagnosis* / Q000201:enzymology; D018656:Muscle Fibers, Fast-Twitch / Q000378:metabolism / Q000473:pathology; D018482:Muscle, Skeletal / Q000473:pathology; D018995:Myosin Heavy Chains / Q000378:metabolism; D009801:Oculomotor Muscles / Q000201:enzymology / Q000473:pathology*; D020033:Protein Isoforms
chemical_list: D020033:Protein Isoforms; D003576:Electron Transport Complex IV; D018995:Myosin Heavy Chains