A series of papers in Gut recently highlighted genetic variation in the sucrase-isomaltase gene ( SI ; coding for a brush-border disaccharidase) as a likely causative factor in a subset of patients with irritable bowel syndrome (IBS).1–4 Hypomorphic (dysfunctional) SI variants may thus underlie gastrointestinal symptoms in rare recessive forms of congenital SI deficiency (CSID)5 as well as milder complex (IBS) manifestations,6 across a broad spectrum of genetic SI deficiencies (GSID) that vary in severity and onset of presentation.7 Moreover, SI carrier status has been shown to also affect the response to specific carbohydrate-focused diets, thus providing a rationale for personalising (dietary) therapeutic strategies in IBS.1 8 Together with SI, a number of human Carbohydrate-Active enZymes (hCAZymes, www.cazy.org/e355.html) are involved in the breakdown of polysaccharides during the process of carbohydrate digestion, which is initiated by salivary amylases (AMYs) and finalised in the small intestine by pancreatic AMYs and brush-border disaccharidases SI, lactase (LCT), maltase-glucoamylase (MGAM) and trehalase (TREH) (figure 1).5 Of note, similar to SI in GSIDs, mutations in other hCAZymes cause rare genetic forms of carbohydrate maldigestion, while regulatory DNA variations (persistent genotype) influence lactose intolerance in adults.5 This suggests hCAZyme genes other than SI may contribute to IBS predisposition via similar mechanisms (reduced hCAZyme activity increasing IBS risk): …

中文翻译：

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人类 CAZyme 基因多态性与 IBS 风险：一项基于人群的研究


《Gut》最近发表的一系列论文强调，蔗糖酶-异麦芽糖酶基因（SI；编码刷状缘双糖酶）的遗传变异是肠易激综合征 (IBS) 患者子集的一个可能致病因素。1-4 低等态（因此，SI 变异可能是罕见隐性形式的先天性 SI 缺陷 (CSID)5 以及较温和的复杂 (IBS) 表现 6 的胃肠道症状的基础，涵盖范围广泛的遗传性 SI 缺陷 (GSID)，其严重程度和发病时间各不相同。 7 此外，SI 携带者状态也已被证明会影响对特定碳水化合物饮食的反应，从而为 IBS 的个性化（饮食）治疗策略提供依据。1 8 与 SI 一起，许多人类碳水化合物活性物质酶（hCAZymes，www.cazy.org/e355.html）参与碳水化合物消化过程中多糖的分解，该过程由唾液淀粉酶 (AMY) 启动，并在小肠中由胰腺 AMY 和刷状缘完成双糖酶 SI、乳糖酶 (LCT)、麦芽糖酶-葡糖淀粉酶 (MGAM) 和海藻糖酶 (TREH)（图 1）。5 值得注意的是，与 GSID 中的 SI 类似，其他 hCAZymes 中的突变会导致罕见的碳水化合物消化不良遗传形式，而调节性 DNA 变异（持续基因型）影响成人乳糖不耐受。5 这表明除 SI 之外的 hCAZyme 基因可能通过类似机制导致 IBS 易感性（hCAZyme 活性降低增加 IBS 风险）：……