GENETIC STUDIES OF CROHN'S DISEASE AND ULCERATIVE COLITIS

炎症性肠病、克罗恩病和溃疡性结肠炎， 慢性经常致残性炎症性疾病的小和 大肠。尽管广泛的免疫学、病理学和 微生物学研究，病因尚不清楚， 病理生理学知之甚少。药物治疗不是最理想的 通常伴随着相当大的发病率。结直肠癌的风险 在这两种疾病中，癌症的发病率都显著增加。 有强有力的证据来自双胞胎研究，家族性研究 疾病患病率的聚集性和种族差异 炎症性肠病(IBD)、克罗恩病(CD)和溃疡性肠病 结肠炎(UC)，在很大程度上是遗传的。这些障碍被归类 作为复杂的遗传疾病，因为遗传并不遵循简单的 孟德尔式的图案。与其他复杂的遗传性疾病相比 兄弟姐妹间的遗传聚集度，用ns和 定义为兄弟姐妹的风险高于人口流行率 先证者，是相对较大的。CD、UC和IBD的NS已被 估计分别为36.5，16.6和24.7，相对较高 而不是其他易感基因已经 更成熟的，如IDDM和精神分裂症，其中ns是15和 8.6。CD和UC在基因上有亲缘关系，因为 CD先证者的疾病相对风险为3.85，UC先证者为1.72 先证者。 我们对IBD的遗传学研究是基于这样一个假设： 与家族性遗传病相关的特异性易感基因 这些疾病的聚集性。易感基因鉴定将 允许了解最初的病理生理机制，以及 从而使设计更好的医疗疗法和更好的 预测病程。

The inflammatory bowel diseases, Crohn's disease and ulcerative colitis, are chronic frequently disabling inflammatory disorders of the small and large intestines. Despite extensive immunologic, pathologic and microbiologic reseerch, the etiology remains unknown, and the pathophysiology is poorly understood. Medical therapy is suboptimal and often associated with considerable morbidity. The risk of colorectal cancer is significantly increased for both disorders. There is strong evidence from twin studies, studies of familial aggregation and ethnic differences in disese prevalence that the inflammatory bowel diseases (IBD), Crohn's disease (CD) and ulcerative colitis (UC), are in large part genetic. The disorders are categorized as complex genetic disorders, since inheritance does not follow simple Mendelian patterns. In comparison with other complex genetic disorders the degree of genetic clustering in siblings, expressed as ns and defined as the increased risk over population prevalence for a sibling of a proband, is relatively large. ns for CD, UC and IBD have been estimated at 36.5, 16.6 and 24.7, respectively, comparatively greater than that for other disorders where susceptibility genes have been better established, such as IDDM and schizophrenia where ns is 15 and 8.6, respectively. CD and UC are genetically related as the cross disease relative risk is 3.85 with a CD proband and 1.72 with a UC proband. Our genetic studies on IBD are based on the hypothesis that there are specific susceptibility genes which are responsible for the familial clustering of these diseases. Susceptibility gene identification will allow an understanding of the initial pathophysiologic mechanisrns, and thus make it possible to design better medical therapy and better predict the disease course.