Mitochondrial myopathy

Overview
Mitochondrial myopathy are a type 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