1. Department of Pediatrics, Japanese Red Cross Society Himeji Hospital, Himeji, Hyogo 670-8547, Japan
2. Department of Child Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo 187-8551, Japan
3. Department of Laboratory Medicine, Uji-Tokushukai Medical Center, Uji, Kyoto 611-0042, Japan