1 Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, 610041, China.
2 Key Laboratory of Obstetric and Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education, Sichuan University, Chengdu, 610041, China.
3 Department of Anesthesiology, West China Second University Hospital, Sichuan University, Chengdu, 610041, China.
4 Department of Pediatrics and Neurology, University of California, San Francisco, CA, 94143, USA.
5 Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, 610041, China. hxlixihong@126.com.