中文摘要：

目的通过对宁夏地区336例聋哑学生进行三种常见致聋基因的筛查，从分子水平了解其遗传病因及特点。方法采集宁夏回族自治区336例非综合征型耳聋学生（汉族167例，回族169例）外周静脉血，提取基因组DNA，应用多聚酶链反应（PCR）扩增GJB2基因编码区、SLC26A4基因第8、19外显子及线粒体DNA（mtDNA）目的基因片段，Alw26I限制性内切酶检测m．1555A〉G点突变，对酶切阳性标本和GJB2基因编码区及SLC26A4基因的第8、19外显子进行DNA测序。分析比较汉族、回族患者中各种突变的等位基因频率。结果336例患者中，有7例（2．08％）存在线粒体DNA12SrRNAm．1555A〉G均质性突变；有45例为GJB2基因突变所致（包括纯合和复合杂合突变），突变频率为13．39％（45／336），11例为单个GJB2杂合突变携带者。c．235delC和C．299—300delAT等位基因频率分别为9．52％（64／672）和2．68％（18／672），占所有G_IB2致病等位基因数的81．19％（82／101），是该群体中的热点突变，各种类型突变的等位基因频率在汉族和回族患者中差异无统计学意义（P值均〉0．05）。28例患者为SLC26A4双等位基因突变，突变频率为8．33％（28／336），32例携带SLC26A4单等位基因突变；c．919-2A〉G和C．2168A〉G占所有SLC26A4碱基改变等位基因数的95．29％（24／27），且这两种突变的等位基因频率在汉族和回族患者中差异具有统计学意义（c．919—2A〉G，χ2=8．229，／9=0．004；c．2168A〉G，χ2=5．277，P=0．022）。结论GJB2基因突变是导致本研究耳聋学生群体听力损失的主要原因，c．235delc是其最常见的突变形式，c，919—2A〉G和c．2168A〉G为SLC26A4基因主要的两种突变形式，其突变率在汉族、回族存在差异。

英文摘要：

Objective To investigate the molecular genetic causes and their characteristics of deafness in Ningxia province, we established screening of three common hereditary deafness genes in 336 deaf and hard-of-hearing patients in this district. Methods Peripheral blood samples were obtained from a total of 336 patients with non-syndromic sensorineural hearing loss in parts of special education schools in Ningxia province to extract genomic DNA. The mitochondrial DNA 12S rRNA m. 1555A 〉 G mutation was screened by PCR Alw26I digestion and sequence analysis PCR and direct sequencing were used to analyze the coding region of GJB2 and exons 8 and 19 of SLC26A4. Statistical analysis was performed by using SPSS 11.0 software. Frequencies of different GJB2 or SLC26A4 mutations were compared between HaM and Hui people. Results Among these 336 patients, seven cases （2. 08%, 7/336） were found to carry mtDNA 12S rRNA m. 1555A 〉 G homozygous mutation, 45 cases （ 13.39% ） were caused by GJB2 mutations and 28 cases （8.33%） had two mutated aUdes （homozygote and compound heterozygote） of SLC26A4. In detail,16.67% （56/336） patients carried GJB2 mutations including 11 single mutant carriers. The allele frequency of c. 235delC and c. 299_300delAT were 9. 52% （64/672） and 2. 68% （ 18/672）, respectively, making up 81.19% （82/101） of all pathogenic mutated alleles for GJB2. The single mutant allele carriers of SLC26A4 is 32, and two types （ c. 919-2A 〉 G and c. 2168A 〉 G） accounted for 95.29% （24/27） mutations, totally. We also found that statistically significant differences in c. 919-2A 〉 G and c. 2168A 〉 G frequencies between Han and Hui people （c. 919-2A 〉 G, X2 = 8. 229,P = O. 004 ;c. 2168A 〉 G, X2 = 5. 277, P = 0. 022）. However, there was no statistically significant difference in GJB2 mutation between Han and Hui people. Conclusions GJB2 mutation was a primary cause for non-syndromic sensorineural hearing loss in Ningxia province, and c. 235delC was the most common mutant for