Mitochondrial myopathy

From Biology-Online Dictionary | Biology-Online Dictionary



A type of myopathy caused by a mitochondrial dysfunction, and characterized by having ragged-red muscle fibers due to glycogen and neutral lipid accumulations


A mitochondrial myopathy is a type of myopathy that is associated with mitochondrial dysfunction. A myopathy is a disease of the muscle. The muscle fibers are not able to function normally. Mitochondrial myopathy is characterized by the presence of ragged-red muscle fibers due to glycogen and neutral lipid accumulations. There is an increase in the number of enlarged mitochondria in the muscle fibers. Some of the common symptoms include generalized weakness, lactic acidosis, exercise intolerance, heart failure or rhythm disturbances, and ophthalmoplegia. Muscle weakness often involves neck, shoulder, and pelvic girdles.

The underlying cause of mitochondrial myopathy is mutation (e.g. deletion or duplication) in the mitochondrial DNA (or in nuclear DNA). There are many types of mitochondrial myopathies. Some of them are as follows:

  • Kearns-Sayre syndrome (KSS)
  • Mitochondrial DNA depletion syndrome (MDS)
  • Mitochondrial encephalomyopathy lactic acidosis and stroke-like episodes (MELAS) syndrome
  • Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE)
  • Myoclonus epilepsy with ragged red fibers (MERRF)
  • Neuropathy, ataxia and retinitis pigmentosa (NARP)
  • Pearson syndrome
  • Progressive external ophthalmoplegia (PEO)

See also: