GpCRC Pediatric Gastroparesis Registry 2

Inclusion Criteria: * Provision of signed and dated informed consent form and assent, as age appropriate. * Stated willingness to comply with all study procedures and availability for the duration of the study * 8 to 25 years of age at the time of enrollment * Symptoms of Gp of at least 12 weeks duration: constellation of some combination of: nausea, vomiting, early satiety, postprandial fullness; symptoms sometimes may be accompanied by upper abdominal pain * Have undergone a gastric emptying scintigraphic study of solids using 4-hour Egg Beaters protocol (or equivalent generic liquid egg white meal) within the last 12 months who fall into one of the two categories: * Delayed gastric emptying-defined as an abnormal 2-hour (\>60% retention) and/or 4- hour (\>10% retention) result based on a 4-hour scintigraphic gastric emptying study * Gastric emptying that is not delayed but who have symptoms of Gp (designated in this study as GLS) or have previously participated in the Pediatric Gastroparesis Registry (PGpR) study * An etiology of either diabetic or idiopathic Gp or GLS Exclusion Criteria: * Inability to comply with or complete the scintigraphic gastric emptying test (including allergy to eggs) * Pregnancy * Autism spectrum disorder, significant developmental delay, psychosis (because of inability to complete questionnaires) * Use of narcotic analgesics greater than three days per week. * Presence of conditions associated with GI mucosal disease (e.g., inflammatory bowel disease, known eosinophilic gastroenteritis or eosinophilic esophagitis, gastric ulcer, peptic ulcer, celiac disease) * Presence of any other condition that could case delayed gastric emptying * Gastrointestinal construction confirmed by upper endoscopy (EGD), upper gastrointestinal series (UGI), or abdominal CT * Primary neurological conditions that can cause nausea and vomiting such as increased intracranial pressure, space occupying or inflammatory/infectious legions * Acute or chronic renal failure (abnormal creatinine for age) and /or on hemodialysis or peritoneal dialysis * Acute liver failure * Advanced liver disease (features of portal hypertension) * Clinically significant congenital heart disease (i.e., vaginal injury during cardiac repair) * History of esophageal, gastric or bowel surgery. * Metabolic disease including mitochondrial disease and inborn errors of metabolism * Chronic lung disease (including cystic fibrosis) * A serious chronic medical condition (e.g., inflammatory bowel disease) * Use of medications that can affect motility during the gastric emptying study * Any other condition, which in the option of the investigator, could explain the symptoms or could interfere with study requirements.