This study is looking at how a medicine called Sucraid® helps kids with a condition called CSID (Congenital Sucrase-Isomaltase Deficiency). CSID affects how the body breaks down sugar. The study will last for 7 days and will include kids aged 6 months to 17 years old. It will check their sucrase levels (an enzyme that helps digest sugar) through a test called EGD (Esophagogastroduodenoscopy). The study is open to kids with different sucrase levels: low, moderate, and normal. Participants will be given Sucraid® to see if it helps with symptoms like diarrhea and stomach pain. The study will involve a Screening Visit, Run-in Period, Baseline Visit, Treatment Period, and Follow-up Visit.

• The study lasts for 7 days and includes several visits.
• Participants must be able to attend all visits and follow study instructions.
• Participants will be using their own mobile devices to complete questionnaires.