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

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 ＜Genetic Testing Kit for Mitochondrial DNA A1555G Mutation＞ 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.