Mitochondria are also known as power houses of the living beings who derive their energy through aerobic process. Any disorder of mitochondria means power house failure and disruption in energy supply. Thats why mitochondrial disorders cause disruption in energy supply to muscles hence leading to disordered muscle function.
Mitochondrial dysfunction is inherited through maternal line. In some cases it is nuclear dysfunction rather than mitochondrial DNA defect hence suggesting some aspects of the mitochondrial function are under nuclear control rather than mitochondrial DNA.
Mitochondrial myopathies is a subgroup of mitochondrial diseases also known as mitochondrial cytopathies. Oxidative metabolism takes place as a result of respiratory chain of mitochondria. Mitochondrial dysfunction leaves no option but anaerobic metabolism by the cells leading to lactic acidosis.