青海省非综合征型耳聋患者线粒体DNA12SrRNA A1555G和GJB2基因突变检测分析

AN EVALUATION OF mtDNA A1555G AND GJB2 MUTATIONS IN PATIENTS WITH NONSYNDROMIC SENSORINEURAL HEARING LOSS IN QINGHAI PROVINCE

目的检测和分析青海省非综合征型耳聋患者线粒体DNA12SrRNA A1555G突变和GJB2突变流行病学特征,为耳聋基因诊断方法和筛查策略提供数据基础。方法应用聚合酶链反应对青海省261例耳聋患者的线粒体12SrRNA基因和GJB2第2外显子基因编码区进行扩增;限制性内切酶Alw26I检测线粒体DNA A1555G突变。对酶切提示A1555G突变的病例和全部GJB2基因扩增产物进行DNA测序。结果在261例患者中,16例携带A1555G突变,突变频率为6.13%,其中汉族10例(7.14%)、回族6例(7.23%),两个民族之间A1555G突变频率无显著性差异(P>0.05);25例具有GJB2已知致病突变,致病突变频率为9.58%,其中汉族20例(14.29%)、回族3例(3.61%)、土族2例(40.00%),汉族GJB2基因突变频率显著高于回族(P<0.05);c.235delC是GJB2基因的突变热点。结论青海省约有15.71%的非综合征型耳聋患者是由GJB2基因或mtDNA A155G突变所致。

Objective To reveal and analyze the characteristics of GJB2 and mitochondrial DNA A1555G mutations in patients with nonsyndromic sensorineural hearing loss in Qinghai Province. Methods 261 subjects in this study were collected from the schools for deafmutes and Outpatient Department in Qinghai province. Amplified the target fragments including GJB2 coding sequence, mtDNA12SrRNA. The amplicons of mtDNA12SrRNA were subjected to restriction enzyme Alw26I. The amplicons of patients whose enzyme reaction highly indicating A1555G mutation and amplicons of GJB2 were directly sequenced . Results The study revealed that 15.71% patients had two mutated alleles （homozygote and compound heterozygote） of GJB2 （9.58%） and mtDNA12SrRNA A1555G （6.13%）. There were no significant difference in mtDNA A1555G mutation frequencies between the Han Chinese and Hui, but GJB2 mutation frequency in Han Chinese was significantly higher than in Hui. The c.235delC was still the mutational hot spot in GJB2. Conclusion About 15.71% of patients with nonsyndromic sensorineural hearing loss patients were caused by the mtDNA A1555G and GJB2 genes mutation in Qinghai province.