Adult Sucrase-isomaltase Deficiency (ASID); An Unrecognized Overlap with Functional Bowel Disease (FBD). an Observational Cross-sectional Study

Abstract

Introduction: Congenital SID is a well-defined entity in the pediatric population with an estimated prevalence of 0.2% in the USA. The symptom complex is well characterized with a triad of abdominal pain, diarrhea and bloating. Over 20% have at-least one episode a month with altered QOL scores. ASID is not well elucidated. FBD has similar clinical presentation with hyperalgesia, bloating and diarrhea. No diagnostic markers are yet available for FBD. ASID is an autosomal recessive disease with predominant clinical phenotype of heterozygotes and compound heterozygotes (with available genomic sequencing). This cross sectional clinical study evaluates the co-existence of ASID with FBD diarrheal subtype Methods: 56 adults (M: F=18:38, with ROME III criteria for IBS-D) aged 18 to 35 were selected and sub-divided into 3 groups: Group A; (n=20, IBS-D with positive methane breath test for SIBO), Group B (n=20, IBS-D) and Group C (n=16, IBS-D with NUD, H Pylori negative) Demographics- to follow Exclusion criteria: Prior diagnosis of SID, diabetes, IBD, scleroderma, recent post viral gastroenteritis, lymphoma, celiac disease, HIV, radiation to small bowel, cirrhosis of the liver, H pylori infection, peptic ulcer disease, Giardiasis, acute infectious gastroenteritis, portal hypertensive gastropathy, mesenteric ischemia, multiple sclerosis, C difficile infection or some medications (antibiotics in past two months, FAD map diet within the last month, herbal medications, PPi within the past month, TCA's, Loperamide, bismuth compounds, any chemotherapy All were tested for the following: Methane 13C breath testing, CBC, SMA 18, TFT, CRP, IBD panel, celiac panel, stool for O and P, Calprotectin, lactoferrin, H pylori IgM, Endoscopy with small bowel biopsy CD3, CD4, CD8, mast cells, Total IgA, Tissue Sucrose, ISO maltose, Lactose, C13 breath testing for SIBO, buccal smear genetic sequencing for ASID on positive tissue sucrose and ISO maltase deficiency Results: The detection of ASID in group A, B and C was 2/20 (10%), 7/20 (35%) and 0/16 (0%) Conclusion: ASID is an undiagnosed clinical state in patients with IBS-D with or without SIBO. Further, in the SIBO cohort ASID was significantly higher (35% compare INS 10% Larger study needs to validate.