title: 13C-breath tests for sucrose digestion in congenital sucrase isomaltase-deficient and sacrosidase-supplemented patients.
abstract: BACKGROUND
  Congenital sucrase-isomaltase deficiency (CSID) is characterized by absence or deficiency of the mucosal sucrase-isomaltase enzyme. Specific diagnosis requires upper gastrointestinal biopsy with evidence of low to absent sucrase enzyme activity and normal histology. The hydrogen breath test (BT) is useful, but is not specific for confirmation of CSID. We investigated a more specific 13C-sucrose labeled BT.
  
  
  OBJECTIVE
  Determine whether CSID can be detected with the 13C-sucrose BT without duodenal biopsy sucrase assay, and if the 13C-sucrose BT can document restoration of sucrose digestion by CSID patients after oral supplementation with sacrosidase (Sucraid).
  
  
  METHODS
  Ten CSID patients were diagnosed by low biopsy sucrase activity. Ten controls were children who underwent endoscopy and biopsy because of dyspepsia or chronic diarrhea with normal mucosal enzymes activity and histology. Uniformly labeled 13C-glucose and 13C-sucrose loads were orally administered. 13CO2 breath enrichments were assayed using an infrared spectrophotometer. In CSID patients, the 13C-sucrose load was repeated adding Sucraid. Sucrose digestion and oxidation were calculated as a mean percent coefficient of glucose oxidation averaged between 30 and 90 minutes.
  
  
  RESULTS
  Classification of patients by 13C-sucrose BT percent coefficient of glucose oxidation agreed with biopsy sucrase activity. The breath test also documented the return to normal of sucrose digestion and oxidation after supplementation of CSID patients with Sucraid.
  
  
  CONCLUSIONS
  13C-sucrose BT is an accurate and specific noninvasive confirmatory test for CSID and for enzyme replacement management.
authors.affiliation: US Department of Agriculture Agricultural Research Service, Children's Nutrition Research Center, Departments of Pediatrics-Nutrition, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Claudia C
authors.initials: CC
authors.lastname: Robayo-Torres
authors.forename: Antone R
authors.initials: AR
authors.lastname: Opekun
authors.forename: Roberto
authors.initials: R
authors.lastname: Quezada-Calvillo
authors.forename: Xavier
authors.initials: X
authors.lastname: Villa
authors.forename: E O
authors.initials: EO
authors.lastname: Smith
authors.forename: Marilyn
authors.initials: M
authors.lastname: Navarrete
authors.forename: Susan S
authors.initials: SS
authors.lastname: Baker
authors.forename: Buford L
authors.initials: BL
authors.lastname: Nichols