死亡受体DR4和DR5基因多态性与克罗恩病的相关性

Associations of Crohn＇s disease with DR4 and DR5 gene polymorphisms

目的探讨死亡受体（deathreceptor，DR）4和DR5基因多态性与克罗恩病（Crohn’Sdisease，CD）的相关性。方法收集295例CD患者和490名对照者，采用SNaPshot技术检测DR4（rsl3278062和rs20575）及DR5（rsl047266）3种单核苷酸多态性（singlenucleotidepolymorphism，SNP）。经非条件Logistic回归分析各SNP的突变等位基因和基因型频率在CD组与对照组之间的差异，以及对CD患者临床病理特征的影响。采用Haploview4．2和R语言软件包进行连锁不平衡及单倍型分析。构建基因-基因交互模型，分析上述3个SNP是否对CD具有协同影响。结果CD组中DR4（rsl3278062）的突变等位基因（T）和基因型（GT＋TT）频率均高于对照组（37．12％7JS．32．04％，P=0．040，95％CI：1．010～1．550；62．71％VS．54．90％，P=0．032，95％CI：11028～1．855），而DR4（rs20575）和DR5（rsl047266）的突变等位基因和基因型频率在两组之间比较差异均无统计学意义（均P〉O．05）。CD患者按“蒙特利尔分型标准”分层，经两两比较校正检验水准后（P〈0．0125），与回结肠型CD相比较，结肠型和回肠末段型CD中DR4（rs13278062）的突变等位基因（T）和基因型（GT＋TT）频率均显著偏高[（结肠型／回结肠型：41．04％VS．25．64％，P=0．002，95％CI：0．315～0．778；66．04％735．41．03％，P=0．001，95％CI：0．196～0．655）；（回肠末段型／回结肠型：41．44％VS．25．64％，P=0．002，95％CI：0．311～0．762；74．77％WS．41．03％，P〈0．001，95％CI：0．126~0．437）]。与穿透型CD相比，狭窄型CD中DR4（rsl3278062）的突变等位基因（T）和突变基因型（GT＋TT）频率均显著降低（32．29％VS．48．91％，P=0．007，95％CI：0．3000．828；57．29％725．86．96％，P=0．001，95％CI：0．078~0．520）；非狭窄非穿透型CD中DR4（rs13278062）的突变基因型（GT＋TT）频率亦显著降低（58．82％WS．86．96％，P=0．001，95％CI：0．086～0．536）。单倍型分析发现DR4（rs20575）-DR4（rs13278062）构建的单倍型CT在CD组中的频率高于对照组（37．1％VS．31．8％，P=0．029，OR=1．279，95％CI：1．022～1．600）。基因-基因交互模型分析显示DR4（rs13278062）的突变基因型（GT＋TT）与DR5（rsl047266）的突变基因型（CT＋TT）可能对CD具有负交互影响（B=-0．483，0R=0．617，P=0．030）。结论DR4（rs13278062）基因突变不仅可能增加CD的发病风险，还可能影响CD患者的疾病部位和疾病行为。DR4（rs20575）和DR4（rs13278062）两个SNP位点构建的单倍型CT可能是CD的危险因子。DR4（rs13278062）和DR5（rs1047266）两个SNP位点的基因突变可能对CD具有负交互影响。

Objective To assess the associations of death receptor DR4 and DR5 gene polymorphisms with Crohn＇s disease （CD）. Methods A total of 295 CD patients and 490 healthy controls were recruited. Three single nucleotide polymorphisms （SNPs） of the DR4 （rs13278062, rs20575） and DR5 （rs1047266） genes were determined with a SNaPshot method. Unconditional logistic regression analysis was carried out for determining the allelic and genotypic differences of the three SNPs between CD patients and the controls, as well as the influence of the DR4 and DR5 gene polymorphisms on the clinical features of CD patients. Linkage disequilibrium and haplotype analysis were calculated by haplotype 4.2 and R language software. A gene-gene interaction model was established to analyze whether the three SNPs can exert a synergistic effect on the susceptibility to CD. Results The mutant allele （T） and genotype （GT-k-TT） of DR4 （rs13278062） were increased among CD patients compared to the controls （37. 12% vs. 32.04%, P= 0. 040, 95%CI： 1.010-1.550; 62. 71% vs. 54. 90%, P= 0.032, 95%CI： 1. 028-1. 855, respectively）. However, the allelic and genotypic frequencies of DR4 （rs20575） and DR5 （rs1047266） did not differ between the two groups （all P〉0.05）. Based on the Montreal Classification Standards, the CD patients were stratified by locations and behaviors of the disease. After multiple comparison correction （P〈0. 0125）, compared to ileocolonic CD patients respectively, the mutant allele （T） and genotype （GT＋TT） of the rs13278062 polymorphism were significantly increased in colonic CD patients （41.04% vs. 25.64%, P= 0. 002, 95% CI= 0.315-0.778; 66.04% vs. 41.03%, P=0.001, 95%CI~ O. 196-0.655, respectively） and terminal ileum CD patients （41.44% vs. 25.64%, P= 0. 002, 95%CI： 0. 311-0. 762; 74.77% vs. 41.03M, P%0. 001, 95 %CI： 0. 126-0. 437, respectively）. In comparison to penetrating CD patients, the mutant allele （T） and genotype （GT ＋ TT） of DR4 （rs13278062） were significantly decreased in stricturing CD patients （32.29% vs. 48.91%, P= 0.007, 95%CI： 0. 300-0.828; 57.29%vs. 86.96%, P= 0.001, 95~CI~ O. 078-0. 520, respectively）. A similar conclusion was drawn for the mutant genotype （GT＋TT） of DR4 （rs13278062） in non-stricturing, non-penetrating CD patients （58.82% vs. 86.96%, P= 0. 001, 95MCI： 0. 086-0. 536）. Haplotype analysis indicated that the CT haplotype formed by rs20575 and rs13278062 was increased in CD patients compared to the controls （37.1% vs. 31.8%, P= 0. 029, OR= 1. 279, 95%CI： 1. 022-1. 600）. The outcome of a gene-gene interaction model indicated that the mutant genotype （GT＋TT） of DR4 （rs13278062） and mutant genotype （CTq-TT） of DR5 （rs1047266） may play a negatively synergistic role in CD patients （B= - 0. 483, OR= 0. 617, P= 0. 030）. Conclusion The rs13278062 polymorphism of the DR4 gene not only can confer an increased risk for CD, but may also influence the location of the lesions and the disease behaviors. The CT haplotype formed by rs20575 and rs13278062 may be an independent risk factor for CD. Furthermore, the mutant genotype （GT＋TT） of DR4 （rs13278062） and mutant genotype （CT＋TT） of DR5 （rs1047266） may exert a negative synergistic effect on CD.