Morphological Markers of Gastroesophageal Reflux Disease (GERD)

Inclusion Criteria for GERD or EoE Subjects: * Children between the ages of 8-18 years * Suspected diagnosis of GERD or EoE based on symptom criteria * Able to tolerate upper endoscopy examination with biopsies Inclusion Criteria for Control Subjects: * Children between the ages of 8-18 * Scheduled for EGD for clinical indications * No history of esophageal disease of esophageal symptoms * Able to tolerate upper endoscopy examination with biopsies Exclusion Criteria for GERD or EoE Subjects: * History of Barrett's esophagus * Previous esophageal or gastric surgery * History of congenital defect/malformation of the esophagus * Diagnosis of Crohn disease Exclusion Criteria for Control Subjects: * Symptoms of GERD or EoE (including heartburn, regurgitation, difficulty swallowing, painful swallowing).