Shuichiro Fujinaga1, Yasuko Urushihara2,3. 1. Division of Nephrology, Saitama Children's Medical Center, 1-2 Shintoshin, Chuo-ku, Saitama city, 330-8777, Japan. f_shuich@d2.dion.ne.jp. 2. Division of Nephrology, Saitama Children's Medical Center, 1-2 Shintoshin, Chuo-ku, Saitama city, 330-8777, Japan. 3. Department of Pediatrics, Saitama Medical Center, Saitama, Japan.