[1] Hokkaido Univ Hosp, Dept Pediat, Sapporo, Hokkaido 0608648, Japan
[2] Hokkaido Univ, Hosp Clin Res, Med Innovat Ctr, Res & Dev Div, Sapporo, Hokkaido 0608648, Japan
[3] Univ Toyama Hosp, Ctr Clin Res, Toyama, Toyama 9300194, Japan
[4] Natl Hosp Org, Nishi Niigata Chuo Natl Hosp, Dept Child Neurol, Niigata 9502085, Japan
[5] Showa Univ, Sch Med, Dept Pediat, Tokyo 1428555, Japan
[6] Hokkaido Univ Hosp, Dept Pediat, North 15, West 7, Kita-ku, Sapporo, Hokkaido 0608638, Japan
[7] Showa Univ, Sch Med, Dept Pediat, 1-5-8 Hatanodai, Shinagawa Ku, Tokyo 1428555, Japan