甘露聚糖结合凝集素基因点突变与类风湿关节炎的关系

Association of the point mutation on mannan binding lectin gene with rheumatoid arthritis

收集类风湿关节炎(RA)患者和正常对照人群血标本,提取白细胞基因组DNA,以PCR扩增目的基因片段并应用荧光探针杂交可视技术检测MBL基因CGT52TGT、GGC54GAC和GGA57GAA点突变,分析MBL基因点突变与RA及其严重程度的关系。72例RA患者中,检出54位密码点突变杂合子29例和纯合子3例、57位密码点突变杂合子1例,其54、57位密码突变的基因频率分别为0.243和0.007;95例正常对照样本中,检出54位密码点突变杂合子22例和纯合子2例、57位密码点突变杂合子1例,其54、57位密码点突变的基因频率分别为0.137和0.005;两者比较,其54位密码点突变有显著差异(x^2=6.78,P<0.05)。有关节侵蚀破坏的43例RA患者中,检出54位密码点突变杂合子21例和纯合子3例,其基因频率为0.314;29例无关节侵蚀破坏的RA患者中,仅有8例54位密码点突变杂合子,基因频率为0.138;两者比较存在显著差异(x^2=6.45,P<0.05)。因此认为,MBL基因点突变是RA的易感因素并与疾病的严重程度有关。

Blood samples were collected from patients with rheumatoid arthritis （RA） and healthy controls in Guangdong province, and the genomic DNA was extracted from leucocytes. The target gene fragment was amplified by PCR, and 3 point mutations in mannan-binding lectin （MBL） gene, CGT52TGT, GGC54GAC and GGA57GAA, gene was detected by fluorogenic probe hybridization technique with visual monitoring. The association of the point mutations with MBL gene and RA and the severity of disease were analyzed. Among 72 patients with RA, 29 and 3 cases were found to be heterozygous and homozygous for point mutation of GGC54GAC and one case was heterozygous for point mutation of GGA57GAA. The frequencies of mutation of GGC54GAC and GGA57GAA were 0. 243 and 0. 007 respectively, compared with 22, 2 and 1, 0. 137 and 0. 005 of healthy controls （χ2 =6. 78, P〈0.05）, while the corresponding figures of GGC54GAC point mutation in 43 patients with radiographic joint destruction were 21, 3 and 0. 314, compared with 8, 0 and 0. 138 in 29 patients with non-erosive RA （χ2=6.45, P〈0.05）. Thus, MBL gene point mutation may be the risk factor for RA and are associated with the disease severity of disease.