Congenital Sucrase-Isomaltase Deficiency (CSID)
(adapted from Pocket Guide to Alaska Native Pediatric Diagnoses)
Pathophysiology: Lack intestinal brush border enzyme to breakdown di- and oligosaccharides including sucrose & isomaltose
Inheritance: Autosomal recessive (potential mild form in carriers)
- likely 3-10% of Alaska Natives (exact numbers not known)
- 3% of Canadian Inuit (28.5% are carriers
- 5-10% of Greenland Inuit
- 0.2% of European-descended North Americans
- Onset usually around the time that solid foods are introduced.
- Watery osmotic diarrhea when fed sucrose-containing food (breast milk and many infant formulas have only lactose), abdominal pain/distention, failure to thrive, malnutrition.
Diagnosis: Genetic Screen (blood), run at University of Washington:
- Test: "Circumpolar 5-mutation panel" (about $1,111)
- Dietary Modification: Avoid sucrose, isomaltose and maltose (corn syrup is sucrose)
- Enzyme Replacement: Sucraid (sucrose digestion only), costs ~$2000/month, not covered by Alaska Medicaid at this time.
Critical Times for Affected Patients:
- Consider first exposed to sucrose (some formulas; most often when starting solids around 6m/o)
- Consider this diagnosis when you have an infant or toddler with chronic diarrhea who has recently started solids or transitioned from breast milk or formula to whole milk and other foods.
- CSID Dietary REcommendations: https://www.csidcares.org/treatment/diet
- ANMC CSID Clinical Guideline