Mitochondrial myopathy are types of myopathy associated with mitochondrial disease.
Examples include:
Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like syndrome (MELAS)
varying degrees of cognitive impairment and dementia
lactic acidosis
strokes
transient ischemic attacks
hearing loss
dysmotility
weight loss
Myoclonic epilepsy and ragged-red fibers (MERRF)
progressive myoclonic epilepsy
clumps of diseased mitochondria accumulate in the subsarcolemmal region of the muscle fiber and appear as "ragged-red fibers" when muscle is stained with modified Gomori trichrome stain
short stature
Kearns-Sayre syndrome (KSS)
external ophthalmoplegia
cardiac conduction defects
sensory-neural hearing loss
Progressive external ophthalmoplegia (PEO)
progressive ophthalmoparesis is the cardinal feature
symptomatic overlap with many other mitochondrial myopathies