1 Department of Pediatrics with Clinical Assessment Unit, Medical University of Warsaw, Ul. Żwirki i Wigury 63A, Warszawa 02-091, Poland. Electronic address: magda.okarska@gmail.com.
2 Department of Pediatrics and Nephrology, Medical University of Bialystok, Ul. Jana Kilińskiego 1, Bialystok 15-089, Poland.
3 Department of Pediatrics with Clinical Assessment Unit, Medical University of Warsaw, Ul. Żwirki i Wigury 63A, Warszawa 02-091, Poland.