Received: 16 March 2018
Accepted: 18 March 2019
First Online: 13 April 2019
Ethics approval and consent to participate
: This research was approved (No.2015–2) by the Ethics Committee of Beijing Children’s Hospital affiliated with Capital Medical University. The protocol (ID: 20150826) was registered in ExternalRef removed. The study was performed after the children and their patents were fully informed. All participants and/or their parents signed an informed consent form and received written and verbal information before participating in this study. All authors read and approved the final manuscript.
: Not applicable.
: The authors declare that they have no competing interests.
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