1. Pediatric Pathology Unit, Department of Pediatrics, Hacettepe University School of Medicine, 06100 Ankara, Turkey
2. Gastroenterology Unit, Department of Pediatrics, Hacettepe University School of Medicine, Ankara, Turkey
3. Department of Biochemistry, Hacettepe University School of Medicine, Ankara, Turkey
4. Department of Biostatistics, Hacettepe University School of Medicine, Ankara, Turkey