摘要目的：探讨解旋酶C诱导干扰素结构域蛋白1基因（IFIH1）的单核苷酸多态性（SNP） rs1990760 C>T与江苏地区汉族PM/DM发病的相关性。方法共纳入183例PM/DM患者和400名健康对照。采用Taqman MGB探针法对rs1990760进行基因分型；采用ELISA法检测抗黑色素瘤分化相关蛋白5（MDA5）抗体；基因型及等位基因的分布频率、Hardy-Weinberg平衡（HWE）采用χ2检验或Fisher确切概率法进行统计分析。结果各患者组和对照组IFIH1 rs1990760的基因型均符合HWE分布。 T和C等位基因频率在PM/DM组（分别为20.8%和79.2%）、DM组（分别为20.9%和79.1%）、PM组（分别为20.5%和79.5%）和对照组（分别为18.0%和82.0%）之间的分布差异无统计学意义。在隐性模型（TT与CT+CC）和加性模型（TT与CC）中，PM/DM组TT基因型频率均显著高于对照组（6.6%与2.8%，χ2值分别为4.8和4.54，P值均为0.03），DM合并间质性肺疾病（ILD）组TT基因型频率均显著高于对照组（8.3%与2.8%，χ2值分别为4.84和4.41，P值分别为0.03和0.04），差异有统计学意义。在隐性模型（TT与CT+CC）中，PM未合并ILD组TT基因型频率显著高于对照组（9.8%与2.8%，χ2=5.56，P=0.04），差异有统计学意义。抗MDA5阳性患者的rs1990760等位基因和基因型分布与对照组差异无统计学意义。结论 IFIH1的rs1990760 TT基因型可能与江苏地区汉族PM/DM易感性相关，且其相关性可能因DM和PM患者是否合并ILD而有所不同。

abstractsObjective To explore the associations between interferon induced helicase C domain 1 (IFIH1) gene single nucleotide polymorphism (SNP) rs1990760 C >T and polymyositis/dermatomyositis (PM/DM) in Chinese Han patients from Jiangsu area. Methods A total of 183 PM/DM patients and 400 healthy controls were included. SNP typing was performed by Taqman MGB probe method. The distributions of genotypes and alleles and Hardy-Weinberg equilibrium (HWE) were examined by χ2 tests or Fisherˊs exact tests. Results The distribution of IFIH1 rs1990760 genotypes of all patients group and the control group were consistent with HWE. The frequencies of T and C alleles were not significantly different between the PM/DM group (20.8% and 79.2%, respectively), the DM group (20.9% and 79.1%, respectively), the PM group (20.5%and 79.5%, respectively) and control group (18.0%and 82.0%, respectively). In recessive model (TT vs CT+CC) and additive model (TT vs CC), the frequencies of TT genotype in PM/DM group (6.6% vs 2.8%; χ2=4.8 and 4.54, respectively; both P=0.03) and in DM with interstitial lung disease (ILD) group (8.3% vs 2.8%;χ2=4.84 and 4.41, respectively; P=0.03 and 0.04, respectively) were significantly higher than those in the control group.In recessive model (TT vs CT+CC), the frequency of TT genotype in PM without ILD group was significantly higher than that in the control group (9.8% vs 2.8%, χ2=5.56, P=0.04). The genotype and allele distributions of rs1990760 were not significantly different between the anti-MDA5 positive group and control group. Conclusion The rs1990760 TT genotype of IFIH1 gene may be associated with the susceptibility of PM/DM in Jiangsu Han Chinese population, and the associations may differ based on the ILD status.