Funding for this research was provided by:
National Natural Science Foundation of China (81870834)
Special Fund of The Pediatric Medical Coordinated Development Center of Beijing Municipal Administration (XTYB201817)
Received: 1 December 2018
Accepted: 14 March 2019
First Online: 10 April 2019
Ethics approval and consent to participate
: This research is approved by ethics committee of Beijing Tiantan Hospital (No. KYSQ 2018-048-1), and the committee consent to publish this article.
: In this study, all patients’ parents or legal guardians have consent to publish.
: The authors declare that they have no competing interests.