Anaplerotic Therapy Using Triheptanoin for Patients With Glycogen Storage Disease Type I

Inclusion Criteria: * Naive to UX007 (triheptanoin) * Confirmed documented diagnosis of GSDI: confirmation may be based on mutation analysis, liver biopsy, or enzyme testing * Willing and able to complete all aspects of the study through the end of the study, including visits and tests, documentation of symptoms, blood sugar and dietary log, and administration of UX007 (triheptanoin); minors in the study must have a parent/legally authorized representative who is willing and able to assist in all applicable study requirements Exclusion Criteria: * Have a history of severe inflammatory bowel disease, or severe chronic diarrhea per the PI discretion on conventional doses of cornstarch * Patient is on any other form of medium chain triglyceride (MCT) during the time of the study. Patients will be asked to stop any nutritional compound that includes MCT oil one week (7 days) prior to baseline. * Have any co-morbid conditions, including major organ-system disease(s) that in the opinion of the Investigator, places the subject at increased risk of complications, interferes with study participation or compliance, or confounds study objectives * Pregnancy * Patients on continuous feeds, with a diagnosis of diabetes, and/or a diagnosis of any other inborn error or metabolism