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 production and osmotic diarrhoea. This information holds potential for patients’ stratification, and the identification of IBS subgroups better suited to benefit from specific dietary restrictions. For instance, diets low in short chain carbohydrates like the FODMAPs (fermentable oligo-, di-, mono-saccharides and polyols that are poorly absorbed in the small intestine) have been shown to be effective in reducing GI symptoms in some patients with IBS,5 6 though this has not been studied in relation to SI genotype and/or function. While sucrose and, in part, starch are not specifically restricted in a standard low FODMAP diet, such a therapeutic approach may be less effective in individuals whose reduced SI activity contributes …

中文翻译：

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低 FODMAPs 饮食对携带蔗糖酶-异麦芽糖酶 (SI) 亚形变体的 IBS-D 患者的疗效降低

最近在肠道和其他地方，1-3 罕见和常见的亚型蔗糖酶-异麦芽糖酶 (SI) 基因变异与 IBS 风险增加有关。类似于先天性 SI 缺乏症（一种由纯合 SI 功能丧失突变引起的碳水化合物吸收不良形式），4 SI 酶活性降低可能通过结肠中未消化的淀粉和蔗糖二糖的积累引发 IBS 症状，导致发酵产生气体和渗透性腹泻。该信息具有对患者进行分层的潜力，以及更适合从特定饮食限制中受益的 IBS 亚组的识别。例如，饮食中短链碳水化合物含量低，如 FODMAPs（可发酵的低聚-、双-、在小肠中吸收较差的单糖和多元醇）已被证明可有效减轻某些 IBS 患者的 GI 症状，5 6 尽管尚未针对 SI 基因型和/或功能进行研究。虽然蔗糖和部分淀粉在标准低 FODMAP 饮食中没有特别限制，但这种治疗方法可能对那些 SI 活性降低有助于……