Val158Met 儿茶酚-O-甲基转移酶（COMT）多态性与肠易激综合征的关系。
The relationship between the val158met catechol-O-methyltransferase (COMT) polymorphism and irritable bowel syndrome.
机构信息
Division of Medicine, Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden.
出版信息
PLoS One. 2011 Mar 18;6(3):e18035. doi: 10.1371/journal.pone.0018035.
BACKGROUND
The catechol-O-methyltransferase (COMT) enzyme has a key function in the degradation of catecholamines and a functional polymorphism is val158met. The val/val genotype results in a three to fourfold higher enzymatic activity compared with the met/met genotype, with the val/met genotype exhibiting intermediate activity. Since pain syndromes as well as anxiety and depression are associated to low and high COMT activity respectively and these conditions are all associated with irritable bowel syndrome (IBS) we wanted for the first time to explore the relationship between the polymorphism and IBS.
METHODOLOGY/PRINCIPAL FINDINGS: 867 subjects (445 women) representative of the general population and 70 consecutively sampled patients with IBS (61 women) were genotyped for the val158met polymorphism and the IBS patients filled out the Hospital-Anxiety-and-Depression-Scale (HADS) questionnaire, and an IBS symptom diary.
RESULTS
There was a significantly higher occurrence of the val/val genotype in patients compared with controls (30% vs 20%; Chi(2) (1) 3.98; p = 0.046) and a trend toward a lower occurrence of the val/met genotype in IBS patients compared with controls (39% vs 49%; Chi(2) (1) 2.89; p = 0.089). Within the IBS patients the val/val carriers exhibited significantly increased bowel frequency (2.6 vs 1.8 stools per day; Chi(2) (1) 5.3; p = 0.03) and a smaller proportion of stools with incomplete defecation (41% vs 68%; Chi(2) (1) 4.3; p = 0.04) compared with the rest (val/met+met/met carriers). The val/val carriers also showed a trend for a smaller proportion of hard stools (0% vs 15%; Chi(2) (1) 3.2; p = 0.08) and a higher frequency of postprandial defecation (26% vs 21%; Chi(2) (1) 3.0; p = 0.08).
CONCLUSIONS/SIGNIFICANCE: In this study we found an association between the val/val genotype of the val158met COMT gene and IBS as well as to specific IBS related bowel pattern in IBS patients.
背景
儿茶酚氧位甲基转移酶（COMT）酶在儿茶酚胺的降解中具有关键作用，其功能多态性为 val158met。与 met/met 基因型相比，val/val 基因型导致酶活性增加三到四倍，而 val/met 基因型则表现出中间活性。由于疼痛综合征以及焦虑和抑郁分别与低和高 COMT 活性相关，而这些情况均与肠易激综合征（IBS）相关，因此我们首次探索了该多态性与 IBS 之间的关系。
方法/主要发现：867 名（445 名女性）具有代表性的普通人群和 70 名连续采样的 IBS 患者（61 名女性）被基因分型为 val158met 多态性，IBS 患者填写了医院焦虑和抑郁量表（HADS）问卷，并填写了 IBS 症状日记。
结果
与对照组相比，患者中 val/val 基因型的发生率明显更高（30%比 20%；卡方（1）3.98；p=0.046），IBS 患者中 val/met 基因型的发生率呈下降趋势（39%比 49%；卡方（1）2.89；p=0.089）。在 IBS 患者中，val/val 携带者的排便频率显著增加（2.6 比 1.8 次/天；卡方（1）5.3；p=0.03），且不完全排便的粪便比例较小（41%比 68%；卡方（1）4.3；p=0.04），与其余患者（val/met+met/met 携带者）相比。val/val 携带者也显示出较小比例的硬便（0%比 15%；卡方（1）3.2；p=0.08）和餐后排便频率增加（26%比 21%；卡方（1）3.0；p=0.08）的趋势。
结论/意义：在这项研究中，我们发现 val158met COMT 基因的 val/val 基因型与 IBS 以及 IBS 患者特定的 IBS 相关排便模式之间存在关联。
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