Received: 2 November 2019
Accepted: 21 July 2020
First Online: 29 July 2020
Ethics approval and consent to participate
: This study was conducted with the approval of the Ethics Committee of Shanghai Children’s Medical Center. An informed consent was obtained from the legal guardian/s.
: All authors have read and approved the content, and they agree to submit it for consideration for publication in the journal.
: The authors declare that they have no competing interests.