A novel mitochondrial tRNA isoleucine gene mutation causing chronic progressive external ophthalmoplegia

Neurology. 1997 Oct;49(4):1166-8. doi: 10.1212/wnl.49.4.1166.


We report a sporadic case of chronic progressive external ophthalmoplegia that developed during childhood and was associated with ragged-red and cytochrome c oxidase (COX)-negative fibers in skeletal muscle. Sequencing of all the mitochondrial transfer RNA (tRNA) genes identified a single potentially pathogenic mutation--a T to C transition at position 4274 in the tRNA(Ile) gene. This mutation was not present in skeletal muscle from 79 controls, and the level of the mutation in COX-negative fibers was significantly greater than the level in COX-positive fibers.

Publication types

  • Case Reports

MeSH terms

  • Adult
  • Chronic Disease
  • Cytochrome-c Oxidase Deficiency
  • Disease Progression
  • Electron Transport Complex IV / metabolism
  • Female
  • Humans
  • Isoleucine / genetics*
  • Muscle Fibers, Skeletal / enzymology
  • Muscle, Skeletal / enzymology
  • Ophthalmoplegia / enzymology
  • Ophthalmoplegia / genetics*
  • Ophthalmoplegia / physiopathology*
  • Point Mutation*
  • RNA / genetics*
  • RNA, Mitochondrial
  • RNA, Transfer / genetics*


  • RNA, Mitochondrial
  • Isoleucine
  • RNA
  • RNA, Transfer
  • Electron Transport Complex IV