Mitochondrial myopathies are a multisystemic group of disorders that are characterized by a wide range of biochemical and genetic mitochondrial defects and variable modes of inheritance. Currently there are no effective treatments for this disease. Despite the heterogeneous myopathy phenotypes, a unifying feature of mitochondrial myopathies is that the pathogenic mtDNA mutations and/or nuclear mutations of the electron transport chain invariably lead to dysfunctional mitochondrial respiration. This reduction in mitochondrial respiration leads to a reduced ability to produce cellular adenosine triphosphate (ATP), often resulting in muscle weakness, exercise intolerance, and fatigue in patients with mitochondrial myopathies.