Functional respiratory chain studies in subjects with chronic progressive external ophthalmoplegia and large heteroplasmic mitochondrial DNA deletions

J Neurol Sci. 1991 Mar;102(1):92-9. doi: 10.1016/0022-510x(91)90098-r.


The functional consequences of large heteroplasmic mtDNA deletions were investigated in a group of 6 patients with chronic progressive external ophthalmoplegia (CPEO) syndromes. State III respiration rates corrected for age were low with site I and II substrates in all cases and cytochrome oxidase activity was depressed. The severity of impairment varied and is consistent with inclusion of a variable percentage of non-functioning mitochondria (with deleted mtDNA) in the pellet. Western blot studies with a holocomplex antibody battery revealed no abnormalities in subunit content of complexes III and IV. A deficiency of several complex I subunits in 3 cases suggests that abnormal nuclear-mitochondrial regulation of complex I assembly may follow large mtDNA deletions.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Chromosome Deletion
  • Cytochrome-c Oxidase Deficiency*
  • DNA, Mitochondrial / genetics*
  • Electron Transport
  • Electron Transport Complex III / deficiency*
  • Electron Transport Complex III / genetics
  • Electron Transport Complex IV / genetics
  • Female
  • Glutamates / metabolism
  • Glutamic Acid
  • Humans
  • Male
  • Middle Aged
  • Mitochondria / metabolism
  • NAD(P)H Dehydrogenase (Quinone)
  • Ophthalmoplegia / genetics
  • Ophthalmoplegia / metabolism*
  • Oxidative Phosphorylation
  • Oxygen Consumption
  • Pyruvates / metabolism
  • Pyruvic Acid
  • Quinone Reductases / deficiency*
  • Quinone Reductases / genetics
  • RNA, Transfer / genetics
  • Succinates / metabolism
  • Succinic Acid


  • DNA, Mitochondrial
  • Glutamates
  • Pyruvates
  • Succinates
  • Glutamic Acid
  • Pyruvic Acid
  • RNA, Transfer
  • Succinic Acid
  • NAD(P)H Dehydrogenase (Quinone)
  • Quinone Reductases
  • Electron Transport Complex IV
  • Electron Transport Complex III