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.