SLE患者DNA甲基转移酶1单核苷酸多态性分析

Screen of single nucleotide polymorphism of DNA methyltransferase 1 in patients with systemic lupus erythematosus

目的比较SLE患者DNMT1基因的单核苷酸多态性，探讨DNMT表达异常在SLE发病中的意义。方法选取SLE患者11例，正常人对照12例。外周血单一核细胞DNA提取后应用PCR结合测序方法检测并分析DNMT1基因的部分外显子exon1～exon7及相应的内含子的单核苷酸多态性，并做进一步基因型分析。结果SLE患者中DNMTl外显子7与8之间内含子7存在21397位T→C（胸腺嘧啶→胞嘧啶）的改变，CC的纯合子较正常人对照组明显增加（r=4．10，P〈0．05）。结论SLE患者DNMT1基因存在单核苷酸多态性，可能是DNMT1基因表达异常的遗传成分之一。

Objective To screen single nucleotide polymorphism （SNP） of DNA methyltransferase 1 gene in patients with systemic lupus erythematosus （SLE）, and to investigate the significance of abnormal expression of DNA methyltransferase in the pathogenesis of SLE. Methods Peripheral blood mononuclear cells （PBMCs） were obtained from 11 patients with SLE and 12 normal human controls. DNA was extracted from the PBMCs, and PCR was performed to amplify some exons （1 to 7） and corresponding introns followed by direct sequencing. Results There was a 21397T/C SNP in the intron 7 between exon 7 and exon 8 of DNA methyltransferase 1 gene in patients with SLE. The frequency of CC homozygote increased in patients with SLE compared with that in normal controls （5/11 vs 1/12, χ^2 = 4.10, P 〈 0.05）. Conclusions There is a 21397T/C SNP in DNA methyltransferase 1 gene in patients with SLE, which may be a component of genetic background underlying the abnormal expression of DNA methyltransferase 1.