Text and Data Mining valid from 2019-02-08
Received: 18 September 2018
Accepted: 25 January 2019
First Online: 8 February 2019
Ethics approval and consent to participate
: The protocol of this study received Ethics Committee approval from Beijing Children’s Hospital.
: All patient guardians gave informed consent to the publication of this study.
: The authors declare that they have no competing interests.
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