Mitochondrial myopathy is neuromuscular disease which is caused by damage to the mitochondrion of the cell, which is an energy-producing cell organelle (structure), serving as a power plant within the cell. Since both nerve cells in the brain and muscles (skeletal and cardiac) require a great deal of energy, they are the mostly damaged when mitochondrial dysfunction occurs. There are several types of mitochondrial myopathies, which include Kearns-Sayre syndrome, myoclonus epilepsy with ragged-red fibers, and mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes.
The symptoms of mitochondrial myopathies include muscle weakness or exercise intolerance, heart failure or rhythm disturbances, dementia, movement disorders, stroke-like episodes, deafness, blindness, droopy eyelids, limited mobility of the eyes, vomiting, and seizures. The prognosis for these disorders ranges in severity from progressive weakness to death. Most mitochondrial myopathies occur before the age of 20, and often begin with exercise intolerance or muscle weakness. During physical activity, muscles may become easily fatigued or weak. Muscle cramping is rare, but may occur. Nausea, headache, and breathlessness are also associated with these disorders.
Although no cure currently exists, there is some hope for a treatment for this whole class of hereditary diseases with the use of an embryotic mitochondrial transplant. Physical therapy may extend the range of movement of muscles and improve dexterity. Vitamin therapies such as riboflavin, coenzyme Q, and carnitine (a specialized amino acid) may provide subjective improvement in fatigue and energy levels in some patients.
Mitochondrial Myopathy (Video)