新疆维吾尔族和汉族非综合征型遗传性聋患者线粒体DNA 12S rRNA A1555G、GJB2及GJB3基因突变研究

Study of mtDNA 12S rRNA A1555G, GJB2, GJB3 gene mutation in Uighur and Han people with hereditary nonsyndromic hearing loss in Xinjiang

目的 分析新疆地区维吾尔族和汉族非综合征型遗传性聋患者线粒体DNA、GJB2、GJB3 基因突变情况,探讨新疆地区维吾尔族非综合征型遗传性聋人群中上述基因突变位点及突变频率与汉族耳聋人群的差异.方法 对93名新疆地区非综合征型遗传性聋患者进行耳聋病因问卷调查和纯音听阈测试,另选取110名听力正常人作为对照组.耳聋组中维吾尔族43例,汉族50例;对照组中维吾尔族56例,汉族54例.收集血样,提取DNA后经聚合酶链反应（PCR）扩增.GJB3基因PCR产物直接测序;针对线粒体DNA 12S rRNA A1555G点突变进行限制性内切酶分析,挑选阳性者进一步测序.对83例非综合征型遗传性聋患者和98例正常人行GJB2基因测序,其中耳聋组维吾尔族43例,汉族40例,对照组维吾尔族46例,汉族52例.结果 93名患者中检测到GJB3基因33C-T2例、766G-A 2例、357C-T 7例以及798C-T4例.8例患者存在线粒体DNA 12SrRNA A1555G突变,其中维吾尔族2例,汉族6例.在耳聋患者中,发现9种GJB2碱基改变：109G-A、233-235delC、79G-A、196G-A、341A-G、564G-A、380G-A、71G-A及35delG.对照组检测到GJB3基因357C-T 4例、798C-T 5例及93C-T 2例.对照组发现9种GJB2基因碱基改变：341A-G、380G-A、457G-A、79-G-A、109G-A、281A-G、21G-T、171G-T及368C-A.线粒体DNA A1555G突变频率在汉族耳聋组与对照组之间差异具有统计学意义（P＜0.05）.GJB2基因79G-A突变在两个民族耳聋组和对照组的分布差异均具有统计学意义（P值均＜0.05）;而341A-G突变在耳聋组两个民族之间的分布差异具有统计学意义（P＜0.05）.GJB3基因798C-T的突变频率无论在耳聋组还是对照组,维吾尔族和汉族之间的差异均具有统计学意义（P值均＜0.05）.结论 新疆地区线粒体DNA 12S rRNA A1555G突变检出率较高.GJB3 基因突变并非新疆地区非综合征型遗传性聋患者的主要致病原因.该地区GJB2和GJB3突变具有种族和地域性特点.

Objective To study mtDNA, GJB2, GJB3 and determine gene mutation situs and frequency in Uighur and Han people with hereditary nonsyndromic hearing loss, and to compare the differences of gene mutation situs and frequency between Uighur and Han people. Methods Blood samples were obtained from 93 patients （43 Uygur and 50 Han） with hereditary non-syndromic hearing loss and 110normal people （56 Uygur and 54 Han）. Genomic DNA was extracted from isolated leukocytes, and amplified by polymerase chain reaction （PCR）. PCR products of GJB3 were sequenced directly; while PCR products of mitochondrial DNA 12S rRNA A1555G point mutations were analyzed by PCR-Alw26I digestion,and positive ones were further sequenced. GJB2 genes of 83 patients （43 Uygur and 40 Han） with hereditary non-syndromic hearing loss and 98 normal people （46 Uygur and 52 Han） were directly sequenced. Results Among GJB3 genes of 93 patients, 2 cases of 33C-T, 2 cases of of 766G-A, 7 cases of 357C-T, and 4cases of 798C-T were detected. Mitochondrial DNA 12SrRNA A1555G mutation was detected in 8 patients （2 Uygur and 6 Han）. Nine kinds of base changes of GJB2 were detected：109G-A, 233-235delC, 79G-A,196G-A, 341A-G, 564G-A, 380G-A, 71G-A, and 35delG. In the control group, detected GJB3 mutations included 4 cases of 357C-T, 5 cases of 798C-T, and 2 cases of 93C-T; while 9 kinds of base changes of GJB2 were detected：341A-G, 380G-A, 457G-A ,79-GA, 109G-A, 281A-G, 21G-T, 171G-T, and 368CA. For mtDNA 12SrRNA A1555G, the difference between study group of and control group of Han people was statistically significant（P＜0.05 ）. For GJB2 mutation 79G-A, the difference between study group and control group was statistically significant （P＜0.05） in both Uygur and Han people; while for GJB2mutation 341A-G, the difference in study group between Uygur and Han people was statistically significant （P＜0.05）. And for GJB3 mutation 798C-T, the difference was statistically significant both between study group and control group, and between Uygur and Han people （P＜0.05）. Conclusions In Xinjiang,mutation rate was high for mtDNA 12SRNA A1555G. while GJB3 gene mutations were not the main cause of the hereditary nonsyndramic hearing loss. There were certain ethnic and geographical characteristics of GJB2and GJB3 mutations.