1. Department of Cardiology, Sakakibara Heart Institute , 3-16-1 Asahi-cho, Fuchu, Tokyo 183-0003 , Japan
2. Department of Cardiology, National Defense Medical College , 3-2 Namiki, Tokorozawa 359-8513 , Japan
3. Department of Surgical Pathology, Tokyo Women's Medical University , 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666 , Japan
4. Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry , 4-1-1 Ogawa-Higashi, Kodaira, Tokyo 187-8551 , Japan
5. Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry , 4-1-1 Ogawa-Higashi, Kodaira, Tokyo 187-8502 , Japan