Routine disaccharidase testing: are we there yet?

Abstract

Purpose of review Disaccharidase testing, as applied to the evaluation of gastrointestinal disturbances is available but it is not routinely considered in the diagnostic work-up. The purpose of this review was to determine if disaccharidase testing is clinically useful and to consider how the results could alter patient management. Recent findings Indicate that carbohydrate maldigestion could contribute functional bowel disorders and negatively impact the fecal microbiome. Diagnostic techniques include enzyme activity assays performed on random endoscopically obtained small intestinal biopsies, immunohistochemistry, stable isotope tracer and nonenriched substrate load breath testing, and genetic testing for mutations. More than 40 sucrase--isomaltase gene variants coding for defective or reduced enzymatic activity have been reported and deficiency conditions are more common than previously thought. Summary The rationale for disaccharidase activity testing relates to a need to fully assess unexplained recurrent abdominal discomfort and associated symptoms. All disaccharidases share the same basic mechanism of mucosal expression and deficiency has far reaching consequences. Testing for disaccharidase expression appears to have an important role in symptom evaluation, but there are accuracy and logistical issues that should be considered. It is likely that specific recommendations for patient management, dietary modification, and enzyme supplementation would come from better testing methods.

Intestinal Disaccharidase Deficiency in Adults: Evaluation and Treatment

“…CSID is an autosomal recessive disorder of carbohydrate metabolism involving the Sucrose-Isomaltase (SI) gene. CSID mutations are more commonly found in IBS patients vs. healthy controls, and symptom expression is heterogenous depending on the biochemical phenotype of the mutation [ 11 , 12 ].…”

“…One biopsy is used to study the architecture of the mucosa and the second is used for analysis of sucrase, maltase, lactase and isomaltase levels per the Dahlqvist method. This method gives precise levels of disaccharidase levels; however, it can be limited by sample error, as two biopsies may not give a complete picture of brush border enzyme activity as enzyme distribution can be patchy [ 12 ]. Biopsies from distal duodenal provide higher yield than those from the proximal duodenum [ 14 ].…”

“…13 C-methane breath testing measures sucrase activity without administering a sucrose load to the patient while the direct challenge sucrose test is cheaper but will provoke symptoms. Breath test results correlate well with intestinal sucrase activity [ 12 ]. However, it is important to note that in practice, SIBO should be ruled out as the presence of bacterial overgrowth can confound sucrose breath test results [ 22 ].…”

Application of The FODMAP Diet in a Paediatric Setting

“…For example, the maltodextrin was used as the placebo when the effect of fructan challenge was being assessed in children who had responded to a low FODMAP diet [ 102 ]. Future studies are needed in this area as validation of the clinical tests for SI deficiency (breath tests, duodenal enzyme activities, genetic testing) could assist in understanding poorly responsive to diagnose unexplainable abdominal symptoms and lead to efficacious therapeutic approaches [ 117 ].…”

Normal Disaccharidase Activity and Disaccharidase Activity in Patients with Functional Enteropathies

“…Необходимо помнить также о 40 полиморфизмах гена сахаразы-изомальтазы, кодирующих дефектную или пониженную ферментативную активность, способствующую нарушению МП [25]. Врожденный или приобретенный дефицит ферментов щеточной каймы приводит к избытку углеводного субстрата в просвете ТК, вследствие чего увеличиваются осмотическое давление и приток воды.…”