Funding for this research was provided by:
the Japan Agency for Medical Research and Development (18ek0109204h0002)
Received: 28 December 2018
Accepted: 14 February 2019
First Online: 28 February 2019
Ethics approval and consent to participate
: This study was approved by the Institute Review Board Committees at the National Center for Child Health and Development (number 518) and performed after obtaining written informed consent from the parents.
: Consent for publication were obtained from all patients or their parents.
: The authors declare that they have no competing interests.
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