柳州市盲聋学校非综合征性聋分子病因学分析--GJB2 235delC突变和线粒体DNA 12SrRNA A1555G突变筛查报告

目的 分析GJB2 235delC突变和线粒体DNA 12SrRNA A1555G突变在广西壮族自治区柳州地区非综合征性耳聋（nonsyndromic hearing impairment，NSHI）患儿中的作用。方法 收集广西壮族自治区柳州聋哑学校的88例非综合征性耳聋患儿的血样，提取DNA后经聚合酶链反应（PCR）分别扩增GJB2基因编码区及线粒体DNA，ApaI酶切分析GJB2 235位点的C缺失突变、Prey—DAF药物性耳聋基因诊断试剂盒分析线粒体1555位点的A—G突变，对GJB2 235delC及线粒体DNA 12SrRNA A1555G的突变率进行统计分析。结果 88例患儿中1例（1．14％）为GJB2 235delC纯合突变；5例（5．68％）为GJB2 235delC杂合突变；4例（4．55％）存在线粒体DNA 12SrRNA A1555G点突变，其中1例同时伴有GJB2 235delC杂合突变。在分子水平能够明确诊断者占11．37％。结论 柳州地区耳聋患者常染色体隐性遗传性耳聋发生率较全国平均水平低，线粒体DNA 12SrRNA A1555G突变发生率偏高。应用基因诊断技术可以在地区性耳聋病因调查中进行快速筛查、诊断，可达到防止聋儿再生、指导聋儿康复等积极效果。

Molecular genetic analysis of GJB2 gene and mtDNA A1555G mutations in nonsyndromic hearing impairment patients in Liuzhou, Guangxi of China

Objective To determine the prevalence of GJB2 235delC and mitochondrial DNA (mtDNA) A1555G mutations in nonsyndromic hearing impairment patients at the Deaf-Blind Shool in Liuzhou, Guangxi. Methods The peripheral blood samples were obtained and DNA templates were extracted by extraction kits. Using polymerase chain reaction (PCR), the code region of GJB2 gene was amplified. The GJB2 235delC mutation was distinguished by Apa I restricted enzyme digestion method. The Prev-DAF Kit for mtDNA A1555G Mutation was used to detect mtDNA A1555G mutation. Results Of 88 nonsyndromic hearing impairment (NSHI) patients, GJB2 235delC was found in 6 cases(1 case was homozygosis, 5 cases were heterozygosis); 4 cases were shown to carry the mtDNA A1555G mutation (1 was compound with GJB2 235delC heterozygosis). Conclusions The incidence of GJB2 gene and mtDNA A1555G mutations among the deaf-mute students in Liuzhou is 11.37%. Molecular genetic screening for these mutations and genetic counseling are effective methods to prevent the occurrence of hereditary hearing loss.