中文摘要：

目的研究中国西北地区回族非综合征型感音神经性聋（nonsyndromic sensorineural hearing loss，NSHL）患者GJB2、SLC26A4及线粒体DNAl555A〉G（mitochondrial DNA 12S rRNA 1555A〉G，mtDNA1555A〉G）三种常见聋病基因的流行病学特征。方法收集中国西北地区420例回族NSHL患者外周静脉血，采用盐析法提取全血DNA后用多聚酶链反应（polymerase chain reaction，PCR）扩增目的基因片段，对A1w26I酶切阳性的mtDNA1555A〉G标本、GJB2基因编码区及SLC26A4基因的第8、19外显子进行DNA测序。结果420例NSHL患者中，11例为mtDNA 1555A〉G突变所致，占2．62％（11／420）；41例为GJB2基因突变所致，包括纯合和复合杂合突变，占9．76％（41／420），是最常见的致聋病因，其中C．235delC等位基因突变频率为6．90％（58／840），占所有致病等位基因的51．33％（58／113），是GJB2最常见的突变方式；20例为SLC26A4双等位基因改变，占4．76％（20／420），其中C．919—2A〉G等位基因突变频率为5．0％（42／840），占所有等位基因碱基改变的68．85％（42／61），是SLC26A4的热点突变形式。结论本研究为本组17．14％（72／420）的NSHL患者明确了病因，GJB2是中国西北地区回族NSHL患者最常见的致聋基因，C．235delC是其最主要的突变形式-c．919—2A〉G是SLC26A4基因的热点突变。

英文摘要：

Objective To investigate the prevalence of GJB2,SLC26A4 and mitochondrial DNA 12S rRNA m. 1555A〉G（mtDNA 155SANG） mutations in Hui ethic group patients with nonsyndromic hearing loss（NSHL） from Northwest China. Methods A total of 420 peripheral blood samples were collected from unrelated Hui ethic group probands with NSHL in Northwest China. Amplified the target gene by polymerase chain reaction （PCR） after extracting genomic DNA from whole blood. The mtDNA 155SANG mutation was detected by PCR--Alw26I digestion , then direct sequencing was used to the positive samples of mtDNA 155SANG , the coding region of GJB2 gene,exon 8 and 19 of SLC26A4 gene. Results There were 11（2. 620//00） cases caused by mtDNA 1555A~G homo- zygous mutation in 420 patients with NSHL. There were 41（9.76%） cases including homozygote and compound heterozygote,caused by GJB2 gene mutation, which was the most frequent deafness--related gene. The allel frequency of c. 235delc accounted for 6.90%,as well as the most frequent（51.33%） mutational pattern in GJB2 gene. There were 20 patients（4.76%） were found earring two allel mutations in SLC26A4 gene. The allel frequency of c. 919-- 2A〉G was 5.0% ,accounting for a total of 68.85% in all base alterations of SLC26A4 gene,which was the major mutant form of SLC26A4 gene. Conclusion GJB2 gene is the most common deafness--gene in Hui ethnic group patients with NSHL from Northwest China,while e. 235de1C is the main mutant form,and c. 919--2A〉G is the hot-spot mutation of SLC26A4 gene. Through this study we can provide the molecular epidemiology basis for Hui ethnic group patients with NSHL from Northwest China in genetic diagnosis,genetic counseling and therapy by associated testing of three frequent hearing loss genes.