Abstract: Objective To examine the mutation frequencies of deafness genes GJB2,SLC26A4,and mitochondrial DNA(mtDNA) 12S rRNA in children associated with non-syndromic hearing loss,and to expand data base of mutation in Chinese,for development of optimal genetic screening services for hearing impairment. Methods Blood samples and clinical data of 220 sporadic cases with non-syndromic hearing loss and 150 normal controls were collected.The GJB2,SLC26A4,and mtDNA 12S rRNA gene of the patients and normal controls were amplified by polymerase chain reaction(PCR),then subjected to automatic DNA sequencing. Results Analysis revealed that 146(66.36%) and 35(15.91%) of 220 patients with hearing loss carried at least 1 mutant allele in GJB2 and SLC26A4 respectively,and 3(1.36%) patients carried mtDNA A1555G mutations.Overall 36 mutations were detected in this cohort of patients,including 2 novel mutations in GJB2 and 1 novel mutation in SLC26A4 respectively.GJB2 gene c.235delC(19.32%)and SLC26A4 gene IVS7-2A>G(9.09%) were the most common pathogenic mutation.3(2%) of 150 normal control carried pathogenic mutations in GJB2 gene. Conclusion This research demonstrated that a high prevalence of GJB2,SLC26A4,and mtDNA A1555G mutations in Chinese children with non-syndromic hearing loss,and expanded data base of common gene of deafness,and discovered 3 novel mutations,which provided basic information for the molecular diagnosis and gene screening of deafness.

Key words: non-syndromic hearing loss, GJB2, SLC26A4, mitochondrial 12S rRNA, mutation

摘要： 目的 分析非综合征型耳聋患儿的GJB2、SLC26A4基因和线粒体12S rRNA突变频率，扩充中国人群常见耳聋基因突变流行病学数据，为发展适合的聋病基因筛查提供数据基础。方法 收集220名散发非综合征型耳聋病例的外周血样本和临床资料;应用聚合酶链反应(PCR)和直接测序，对患者和150例正常对照进行GJB2、SLC26A4基因和线粒体12S rRNA突变检测。结果 1)220例患者中146(66.36%)例患者携带至少1个GJB2基因突变，35(15.91%)例患者携带至少1个SLC26A4基因突变，3(1.36%)例为线粒体A1555G突变。正常对照中3(2%)例携带GJB2致病突变。2)GJB2基因c.235delC(19.32%)突变是最常见的致病突变，其次是SLC26A4基因IVS7-2A>G(9.09%)突变。3)检出的36种突变中，包括2种GJB2和1种SLC26A4新突变。结论 本研究扩充了GJB2基因、SLC26A4基因和线粒体DNA A1555G突变在中国人群中的基因突变数据，并发现了3种新的突变，为分子诊断和扩展聋病基因筛查提供数据参考。

关键词: 非综合征型耳聋, GJB2, SLC26A4, 线粒体12S rRNA, 突变