Phenotypic diversity associated with the mitochondrial m.8313G>A point mutation

Muscle Nerve. 2009 Oct;40(4):648-51. doi: 10.1002/mus.21342.


We report the clinical, histochemical, and molecular genetic findings in a patient with progressive mitochondrial cytopathy due to the m.8313G>A point mutation in the mitochondrial tRNA(Lys) (MTTK) gene. The clinical features in this case are severe, including short stature, myopathy, peripheral neuropathy, and osteoporosis, while extensive analysis of maternal relatives indicate that the mutation has arisen de novo and was not maternally inherited. This report of a second case, together with single muscle fiber mutation analysis that shows clear segregation of mutation load with cytochrome c oxidase deficiency, confirms that the mutation is pathologic.

Publication types

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

MeSH terms

  • Adult
  • Body Height
  • Electromyography
  • Electron Transport Complex IV / genetics
  • Humans
  • Male
  • Mitochondrial Myopathies / genetics*
  • Mitochondrial Myopathies / physiopathology
  • Muscle Fibers, Skeletal / pathology
  • Muscle, Skeletal / pathology
  • Neural Conduction
  • Osteoporosis / genetics
  • Osteoporosis / pathology
  • Peripheral Nervous System Diseases / genetics
  • Peripheral Nervous System Diseases / pathology
  • Phenotype
  • Point Mutation / genetics*
  • Point Mutation / physiology
  • RNA, Transfer, Lys / genetics*


  • RNA, Transfer, Lys
  • Electron Transport Complex IV