Reduced efficacy of low FODMAPs diet in patients with IBS-D carrying sucrase-isomaltase (SI) hypomorphic variants

Recently in Gut and elsewhere,1–3 rare and common hypomorphic sucrase-isomaltase ( SI ) gene variants have been linked to an increased risk of IBS. Similar to congenital SI deficiency (a form of carbohydrate malabsorption caused by homozygous SI loss-of-function mutations),4 reduced SI enzymatic activity may trigger IBS symptoms via colonic accumulation of undigested disaccharides from starch and sucrose, resulting in fermentation with gas...