儿童双耳感音神经性聋临床特点及GJB2与GJB3基因突变分析

Clinical features and mutation analysis of GJB2 and GJB3 genes in children with binaural sensorineural hearing loss

摘要:

目的 探究并分析儿童双耳感音神经性聋临床表现特点及缝隙连接蛋白26（GJB2）、缝隙连接蛋白31（GJB3）基因突变情况。方法 本研究选取2020年3月—2021年3月接受治疗的150例双耳感音神经性聋患儿作为研究对象，纳入研究组；选择同期参与体检的150例听力正常的儿童作为对照组。试剂盒法提取血液白细胞中的基因组DNA，GJB2、GJB3基因采用编码区聚合酶链反应（PCR）进行检测。观察两组儿童GJB2和GJB3基因检测结果及研究组儿童耳聋程度、不同程度双耳感音神经性聋儿童的GJB2和GJB3耳聋基因突变率及基因突变位点情况、研究组儿童双亲GJB2、GJB3基因突变情况。结果 研究组儿童GJB2基因突变共50例（33.33%），基因致病突变5种（35insG、95G>A、176-191del16、235delC、257C>G），40例与235delC突变相关，占比80.00%；多态性基因改变3种（79G>A、341A>G、427C>T）；GJB3基因突变共6例（538C→T、547G→A）。对照组儿童GJB2基因突变共计3例（2.00%），基因致病突变有两种（95G>A、235delC）；多态性基因改变有两种（79G>A、341A>G）；未发现GJB3基因突变。研究组儿童235delC突变率显著高于对照组（P<0.05）；研究组儿童中重度及极重度患者占达到59.33%（89/150）；不同程度双耳感音神经性聋儿童GJB2、GJB3基因突变率中极重度阳性检出率较高，分别为33.33%和7.5%；重度和危重度患儿致病突变位点例数显著高于轻中度患儿，多态性改变例数低于轻中度患儿（P均<0.05）。研究组儿童父母中发现GJB2基因突变父亲17例（5.67%）、母亲25例（8.33%）；GJB3基因突变父亲3例（1.00%），母亲1例（0.33%）；父母亲均未检验出纯合突变和复合杂交突变以及GJB3基因突变。结论 目前临床暂无对双耳感音神经性聋的有效预防和诊断手段，而GJB2、GJB3基因突变检测可以作为产妇产前诊断的一种方法，从而对下一代进行预防，利于有效诊断耳聋的发生率，从而做到尽早预防，降低发病率。

Abstract:

Objective To explore and analyze the clinical characteristics of children with binaural sensory nerve deafness and the mutations of Gap Junction Beta 2 protein GJB2 (connexin 26, Cx26) and the Gap Junction protein Beta 3 (GJB3).Methods In this study, 150 children with binaural sensorineural hearing loss who were treated from March 2020 to March 2021 were selected as the research objects as an experimental group. And 150 children with normal hearing who participated in the physical examination during the same period were selected as the control group. Genomic DNA was extracted from leukocytes by kit method, and GJB2 and GJB3 genes in the coding region were detected by polymerase chain reaction (PCR). The results of GJB2 and GJB3 gene detection in the two groups were analyzed. It was analyzed for the mutation rates and mutation sites of GJB2 and GJB3 deafness genes in children with different degrees of binaural sensorineural deafness. The mutations of GJB2 and GJB3 were observed in parents of deafness children in the study group.Results In the study group, 50 children (33.33%) had GJB2 gene mutation.There were 5 pathogenic mutations in GJB2 gene(35insG, 95G>A, 176-191del16, 235delC, 257C>G). There were 40 cases related to 235delC mutation, accounting for 80.00%. There were 3 kinds of polymorphic gene changes(79G>A, 341A>G, 427C>T).There were 6 cases of GJB3 gene mutation(538C→T, 547G→A).A total of 3 children in the control group had GJB2 gene mutations(2.00%)including two pathogenic mutations(95G>A, 235delC) and two polymorphic gene changes(79G>A, 341A>G), but not in GJB3 gene. The mutation rate of 235delC in children in the study group was significantly higher than that in the control group(P<0.05). The children with moderate to severe binaural sensorineural hearing loss were accounted for 59.33%(89/150). The mutation rates of GJB2 and GJB3 deafness genes in children with different degrees of binaural sensorineural hearing loss were significantly higher, which were 33.33%and 7.5% respectively. The number of pathogenic mutation sites in the severe and critical children was significantly higher than that in the mild-to-moderate children. The number of cases of polymorphism change in severe and critical children was lower than that in the mild-to-moderate group(all P<0.05).In the study group, GJB2 gene mutation was found in 17 fathers (5.67%) and in 25 mothers (8.33%). There were 3 fathers (1.00%) and 1 mother (0.33%) with GJB3 gene mutation, neither of the parents had detected 2 homozygous mutations, coincident hybrid mutations and GJB3 gene mutations.Conclusions At present, there is no clinically effective means to prevent and diagnose binaural sensorineural hearing loss. GJB2 and GJB3 gene mutation detection can be used as a method of prenatal diagnosis for the mother, so as to prevent the next generation and help effectively diagnose the occurrence of deafness rate with early prevention and reduction of morbidity.