前庭水管扩大患者人工耳蜗植入及SLC26A4基因的突变分析

目的 分析伴前庭水管扩大（EVA）的遗传性耳聋患者SLC26A4基因的突变特点，探讨该病行人工耳蜗植入时应注意的问题。方法 收集伴有EVA的常染色体隐性遗传性耳聋家系5个，经PCR、DNA直接测序法对SLC26A4基因21个外显子及其侧翼区进行突变检测。5个先证者均经乳突一面隐窝进路行人工耳蜗植入，观察术中改变和术后开机效果。结果 在其中一个常染色体隐性遗传家系发现SLC26A4基因的IVS7—2A〉G和IVS10-12T〉A的复合杂合突变，另一个常染色体隐性遗传家系发现SLC26A4基因的1229C〉T和754T〉C的复合杂合突变，其中IVS10—12T〉A为新发现的突变。术中所有蜗内电极均顺利插入，并经术中阻抗和神经遥测（NRT）测试效果满意。3例发生“脑脊液井喷”，用软组织和耳脑胶封堵耳蜗造孔后停止。术后1月开机均成功并重建听力。结论 前庭水管扩大（EVA）患者人工耳蜗植入应注意处理“脑脊液井喷”，防止外淋巴瘘。SLC26A4基因突变是导致该病的分子基础，术前基因诊断对手术有指导作用。

Cochlear implantation for patients with enlarged vestibular aqueduct(EVA) and mutation detection for SLC26A4 gene

Objective To probe the problems that should be paid attention to in cochlea implantation for inherited deafness patients with EVA and to detect the SLC26A4 gene mutation underlying the disease. Methods Five autosomal recessive inheritance genealogies with EVA were collected in the study. The 21 exons and flanking region of the SLC26A4 gene were amplified by polymerase chain reaction(PCR),and direct DNA sequencing was performed to screen for mutations in the SLC26A4 gene. Five probands from these families received cochlear implant through mastoid process-facial recess approach,and the encounting problems during the operation and the outcome after the operation were reviewed. Results We found IVS7-2A > G and IVS10-12T > A compound mutation in SLC26A4 gene in one genealogy with autosomal recessive inheritance and 1229C > T and 754T > C compound mutation in another one,among them the IVS10-12T > A is a novel mutation. All the electrodes were inserted successfully and confirmed intact by electrode impedence testing. CSF gusher took place in three of them during the implantation and were stopped by bunging with soft issue and encephalon glue. One month after the operation all of the cochlear implants worked successfully. Conclusion We should pay attention to the CSF gusher during cochlear implantation in patients with EVA. The SLC26A4 gene mutation is the molecular basis of the disease and pre-operation gene diagnosis is instructive to operation.