The mitochondrial disease is a disorder resulting of the deficiency of one or more proteins located in the mitochondria and involved in the metabolism. The mitochondrial disease cause the greater damage to the cells of the brain, heart, liver, skeletal muscles, kidneys; and, endocrine and respiratory system. Depending of wich cells of the body are affected, the symptoms might include: Loss of the motor control. Muscle weakness and pain. Gastrointestinal disorders. Difficulties to swallow. Growth retardation. Cardiac diseases. Hepatic diseases. Diabetes. Respiratory complications. Visual / hearing problems. Lactic acidosis. Developmental delays. Neurological problems. Increased risk of infection. Dementia.