非综合征型聋患者GJB2 235delC及线粒体DNA A1555G突变分析

目的 对非综合征型聋患者进行聋病分子病因学分析。方法 对北京第三聋哑学校学生进行耳聋病因问卷调查、纯音测听检查，应用PCR扩增及限制酶切方法对158名非综合征型感音神经性聋患者进行GJ-B2和线粒体DNA12SrRNAA1555G基因突变的检测。结果 在158例感音神经性聋患者中，5例（3．16％）存在线粒体DNA12SrRNAA1555G点突变，其中2例有明确的氨基糖甙类抗生素用药史；24例（15．18％）存在GJB2235delC纯合性突变；12例（7．59％）存在GJB2 235delC杂合性突变。在基因水平明确诊断或强烈提示遗传性聋者占25．93％。结论 对GJ-B2 235delC突变和线粒体DNA12SrRNAA1555G突变的基因筛查可以明确或提示部分非综合征型聋的病因，对防聋、指导聋儿家庭婚育及评估人工耳蜗手术预后起到重要作用。

Analysis of GJB2 Gene 235 delC and mtDNA 12S rRNA A1555G Mutations in Nonsyndromic Hearing Impairment Patients

Objective To determine the prevalence of GJB2 235 delC and mitochondrial DNA(mtDNA) A1555G mutations in nonsyndromic hearing impairment patients from Beijing Third School for the deaf.Methods The peripheral blood samples were obtained and DNA templates were extracted by extraction kits. Using polymerase chain reaction, the coding region of GJB2 gene was amplified. The GJB2 235 delC mutation was distinguished by Apa I restricted enzyme digestion method. The was used to detected mtDNA A1555G mutation.Results Among 158 patients, GJB2 235delC was found in 36 cases (24 cases were homozygosis, 12 cases were heterozygosis); 5 cases were found to carry the mtDNA A1555G mutation.Conclusion The detection rate of GJB2 235delC and mtDNA A1555G mutation is 25.93% in nonsyndromic hearing loss patients in Beijing.This is some what higher than the nationwide average level. Genetic testing and genetic counseling will play an important role in preventing the occurrence of hereditary hearing loss.