The purpose of this study is to look for specific changes in the children's bodies responsible for digesting table sugar and also to see if the changes can be seen in a breath test. People who cannot digest sugar often have chronic diarrhea and/or chronic abdominal pain, including children 18 years of age or younger. After common causes for the chronic diarrhea or chronic abdominal pain are ruled out, more rare conditions such as congenital sucrase-isomaltase disorder (CSID) are often not evaluated. The sucrase-isomaltase (SI) gene has coding to make an enzyme needed to digest sugar. When there is a mutation in the SI gene, patients with CSID often experience chronic diarrhea and/or chronic abdominal pain. Assessing the SI gene for these select mutations commonly found in CSID patients and a breath test will be two ways to rule out the possibility for CSID.
Primary Clinical Objective: Confirm a new screening paradigm for CSID based on genetic testing.
- Prevalence of CSID genetic variants in the subject population: Determine the prevalence of CSID genetic variants (Analyzed Variants) in subjects 18 years of age or younger with a primary symptom of chronic idiopathic diarrhea or chronic abdominal pain without constipation.
- Prevalence of low sucrase activity in subjects with CSID variants: Determine if subjects with CSID genetic variants have reduced in vivo sucrase enzymatic activity as measured by 13C-sucrose oxidation.
- Prevalence of low sucrase activity in symptomatic controls: Determine if symptomatic control subjects experiencing a primary symptom of chronic idiopathic diarrhea or chronic abdominal pain without common CSID variants in the sucrase-isomaltase (SI) gene have reduced in vivo sucrase enzymatic activity as measured by 13C-sucrose oxidation.
- Compare rates of low sucrase activity between subjects with CSID variants and symptomatic controls: Determine the range and compare the rates of functional sucrase enzymatic deficiency as measured by a 13C-sucrose breath test for those with CSID Analyzed Variants and symptomatic controls.
- Record data on rates of sucrase activity via disaccharidase assay if available: Compare the frequency of sucrase enzymatic deficiency from disaccharidase assays in both subjects with Analyzed Variants and symptomatic controls who have clinical indications for EGD.
Principal Investigator: Molly O'Gorman
Department: Pediatric Administration