Received: 6 December 2020
Accepted: 31 March 2021
First Online: 14 June 2021
: The study was approved by the ethics committee of the Faculty of Medicine, Assiut University (IRB no: 17101284). Written informed consents were taken from parents with explanation of benefits of the study; risks expected and suggested treatment for each case.
: Not applicable
: The authors declare that they have no competing interests.