耳聋患者及正常人GJB2基因的突变筛查

目的 检测常染色体隐性遗传耳聋患者GJB2基因突变情况,并分析其与临床表型的关系.方法 收集42例耳聋患者的临床资料,对患者进行纯音电测听检查、声阻抗检测、脑干听觉诱发电位检查;应用聚合酶链反应和直接测序法,对患者和9例患者的父母以及105名正常对照进行GJB2基因检测.结果 两例患者具有235delC纯合性突变,其中1例系感音神经性耳聋,另1例系混合性耳聋;1对混合性耳聋的双生子患者同时携带176de116bp杂合性突变.109G→A、79G→A和341A→G的纯合及杂合突变在患者及正常对照中均有出现.结论 235delC纯合性突变为致病突变,该突变可出现在混合性耳聋中;双生子患者的176de116bp杂合性突变考虑为宫内受到外界环境影响所致,或者由其它基因突变所致.109G→A、79G→A和341A→G考虑为是该基因的多态性,其临床意义仍需进一步探索.

GJB2 gene mutation in deaf patients

Objective To detect the GJB2 gene mutation in patients with autosomal-recessive deafness, and analyze the relationship between clinical phenotype and gene mutation. Methods Forty-two patients were examined clinically by pure tone audiometry, acoustic impedance and auditory brainstem response. The complete coding region of the GJB2 gene was amplified by polyrnerase chain reaction (PCR) and the PCR products were subjected to automatic DNA sequencing. Results Two eases had homozygous mutation of 235delC. One of them had sensorineural hearing loss while the other had mixed hearing loss. Heterozygous mutation of 176de116bp was detected in a pair of twins who had mixed hearing loss. The 109G to A, 79G to A and 341A to G mutations were observed in both the patients and the controls. Conclusion Homozygous 235delC mutation is one of the pathogenic mutations which could occur in patients with mixed hearing loss. The heterozygous 176de116bp mutation combined with environmental factor may cause hearing loss. The 109G to A, 79G to A and 341A to G variants were considered to be polymorphisms of the GJB2 gene.