Mitochondrial disease can result from either nuclear DNA mutation (mendelian inheritance) or mt DNA mutations (matemal inheritance).In general, when the clinical presentation is in childhood, the patient will be short statured and the course of the disease will be more severe. Certain features may be in common, e.g. sensorineural hearing loss, dementia, neuropathies, glucose intolerance elevated serum and CSF lactic acid. Red fibers (RREs) on muscle biopsy are of great significance.