Genetic Carbohydrate Maldigestion As Model to Study Food Hypersensitivity Mechanism (WORK PACKAGE 2)

Inclusion criteria

for CSID subjects:

• Aged ≥18 (all groups)
• Subjects with genetically proven CSID
• Previous negative endoscopy with biopsies excluding IBD or microscopic colitis in people above 50 years old.
• Negative relevant additional screening (including exclusion of coeliac disease with TTG and IgA)
• Ability to conform to the study protocol including the sucrose challenge.

Exclusion criteria

for CSID subjects:

• Subjects on opioids and use of drugs known to alter GI motility for the duration of the study.
• Presence of concurrent organic gastrointestinal disease (inflammatory bowel disease, coeliac disease, cancer), or a major disease such as diabetes, uncontrolled thyroid disease
• Any history of bowel surgery (not appendectomy or cholecystectomy)
• Contraindication to MRI scanning
• Having taken part in another interventional research study within 3 months
• Concurrent major confounding condition (e.g. alcohol or substance abuse in the last 2 years) based on the study clinician's judgement.

Inclusion criteria

for healthy participants:

• Aged ≥18 years
• Absence of Rome III IBS criteria
• Non-SI variant confirmed (group 1) or Single-SI variants confirmed (group 2) or Double - SI variants confirmed (group 3)
• Ability to conform to the study protocol including the sucrose challenge

Exclusion criteria

for healthy participants:

• Person presenting with a functional or organic GI disorder.
• Person presenting with underlying disease that may involve the GI tract (e.g. Parkinson's disease) or be associated with GI symptoms (e.g. anorexia nervosa, major depression).
• Any history of bowel surgery (not appendectomy or cholecystectomy)
• Contraindication to MRI scanning
• Having taken part in another interventional research study within 3 months
• Concurrent major confounding condition (e.g. alcohol or substance abuse in the last 2 years) based on the clinician's judgement.