Mar 29, - Mitochondria what's that? Mitochondrial disease in adults is a complicated disorder to diagnose. It has myriad signs and symptoms and body. Jul 6, - The main symptoms of mitochondrial myopathy are muscle fatigue, weakness, and exercise intolerance. People with mitochondrial myopathies also may experience muscle weakness in their arms and legs.What are the symptoms of · Are there specific · How are mitochondrial.