Soree Ear Clinic, Seoul, Korea.
Clin Exp Otorhinolaryngol. 2012 Apr;5 Suppl 1(Suppl 1):S10-3. doi: 10.3342/ceo.2012.5.S1.S10. Epub 2012 Apr 30.
Genetic hearing loss is highly heterogeneous and more than 100 genes are predicted to cause this disorder in humans. In spite of this large genetic heterogeneity, mutations in SLC26A4 and GJB2 genes are primarily responsible for the major etiologies of genetic hearing loss among Koreans. The purpose of this study is to investigate the genetic cause of deafness in Korean cochlear implantees by performing a genetic screening of the SLC26A4 and GJB2 genes.
The study cohort included 421 unrelated Korean patients with sensorineural hearing loss (SNHL) and who had received cochlear implants (CI) at Soree Ear Clinic from July 2002 to December 2010. Among 421 CI patients, we studied 230 cases who had received the genetic screening for SLC26A4 or GJB2 genes. Written informed consent was obtained from all participants. All patients had severe to profound, bilateral hearing loss. For 56 patients who showed enlarged vestibular aqueduct on their computed tomography (CT) scan, we analyzed SLC26A4. For 174 CT negative patients, GJB2 gene was sequenced.
For the 56 SLC26A4 patients, 32 (57.1%) had two pathogenic recessive mutations in SLC26A4. A single recessive SLC26A4 mutation was identified in 14 patients (25%). H723R and IVS7-2A>G were the most commonly found mutations, accounting for 60.3% (47/78) and 30.8% (24/78) of the mutated alleles, respectively. For the 174 GJB2 patients, 20 patients (11.5%) had two pathogenic recessive mutations in GJB2. 235delC was the most common mutation, accounting for 43.0% (31/72) of mutant alleles.
The two major genes, SLC26A4 and GJB2, contribute major causes of deafness in CI patients. Continuous studies are needed to identify new genes that can cause hearing loss to Korean CI patients.
遗传性听力损失具有高度异质性，据预测有超过 100 个基因可导致人类出现这种疾病。尽管存在如此大的遗传异质性，但 SLC26A4 和 GJB2 基因突变主要导致韩国遗传性听力损失的主要病因。本研究的目的是通过对 SLC26A4 和 GJB2 基因进行遗传筛查，来研究韩国人工耳蜗植入患者耳聋的遗传原因。
研究队列包括 421 名无血缘关系的韩国感音神经性听力损失（SNHL）患者，他们于 2002 年 7 月至 2010 年 12 月在 Soree 耳科诊所接受了人工耳蜗植入（CI）。在 421 名 CI 患者中，我们研究了 230 名接受 SLC26A4 或 GJB2 基因遗传筛查的患者。所有参与者均获得书面知情同意。所有患者均有严重至极重度、双侧听力损失。对于 56 名 CT 扫描显示前庭导水管扩大的患者，我们分析了 SLC26A4。对于 174 名 CT 阴性患者，我们对 GJB2 基因进行了测序。
对于 56 名 SLC26A4 患者，有 32 名（57.1%）患者的 SLC26A4 存在两个隐性致病突变。14 名患者（25%）存在单个隐性 SLC26A4 突变。H723R 和 IVS7-2A>G 是最常见的突变，分别占突变等位基因的 60.3%（47/78）和 30.8%（24/78）。对于 174 名 GJB2 患者，有 20 名（11.5%）患者的 GJB2 存在两个隐性致病突变。235delC 是最常见的突变，占突变等位基因的 43.0%（31/72）。
SLC26A4 和 GJB2 这两个主要基因是导致 CI 患者耳聋的主要原因。需要不断研究以确定可导致韩国 CI 患者听力损失的新基因。
