Received: 7 August 2019
Accepted: 24 April 2020
First Online: 1 May 2020
Ethics approval and consent to participate
: This study was approved by the institutional review board of Seoul National University Bundang Hospital (IRB number: B-1803/456–303). Informed consent was obtained from all patients’ parent or their guardians.
: Not applicable.
: The authors declare that they have no competing interests.