Central laboratory, Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, China.
Department of Otolaryngology, Fuyang Second People's Hospital, Hangzhou, China.
Biosci Rep. 2020 May 29;40(5). doi: 10.1042/BSR20200778.
Mitochondrial 12S rRNA A1555G and C1494T mutations are the major contributors to hearing loss. As patients with these mutations are sensitive to aminoglycosides, mutational screening for 12S rRNA is therefore recommended before the use of aminoglycosides. Most recently, we developed a novel multiplex allele-specific PCR (MAS-PCR) that can be used for detecting A1555G and C1494T mutations. In the present study, we employed this MAS-PCR to screen the 12S rRNA mutations in 500 deaf patients and 300 controls from 5 community hospitals. After PCR and electrophoresis, two patients with A1555G and one patient with C1494T were identified, this was consistent with Sanger sequence results. We further traced the origin of three Chinese pedigrees. Clinical evaluation revealed variable phenotypes of hearing loss including severity, age at onset and audiometric configuration in these patients. Sequence analysis of the mitochondrial genomes from matrilineal relatives suggested the presence of three evolutionarily conserved mutations: tRNACys T5802C, tRNALys A8343G and tRNAThr G15930A, which may result the failure in tRNAs metabolism and lead to mitochondrial dysfunction that was responsible for deafness. However, the lack of any functional variants in GJB2, GJB3, GJB6 and TRMU suggested that nuclear genes may not play active roles in deafness expression. Hence, aminoglycosides and mitochondrial genetic background may contribute to the clinical expression of A1555G/C1494T-induced deafness. Our data indicated that the MAS-PCR was a fast, convenience method for screening the 12S rRNA mutations, which was useful for early detection and prevention of mitochondrial deafness.
线粒体 12S rRNA A1555G 和 C1494T 突变是导致耳聋的主要原因。由于这些突变的患者对氨基糖苷类药物敏感，因此在使用氨基糖苷类药物之前，建议对 12S rRNA 进行突变筛查。最近，我们开发了一种新型的多重等位基因特异性 PCR（MAS-PCR），可用于检测 A1555G 和 C1494T 突变。在本研究中，我们使用这种 MAS-PCR 对来自 5 家社区医院的 500 名耳聋患者和 300 名对照者进行了 12S rRNA 突变筛查。经过 PCR 和电泳，发现 2 例患者存在 A1555G 突变，1 例患者存在 C1494T 突变，这与 Sanger 测序结果一致。我们进一步追踪了这 3 个中国家系的起源。临床评估显示，这些患者的耳聋表型存在差异，包括严重程度、发病年龄和听力图模式。对母系亲属线粒体基因组的序列分析表明存在 3 个进化保守的突变：tRNACys T5802C、tRNALys A8343G 和 tRNAThr G15930A，这可能导致 tRNA 代谢失败，并导致线粒体功能障碍，从而导致耳聋。然而，GJB2、GJB3、GJB6 和 TRMU 中没有任何功能变体，这表明核基因可能不会在耳聋表达中发挥积极作用。因此，氨基糖苷类药物和线粒体遗传背景可能导致 A1555G/C1494T 诱导的耳聋的临床表达。我们的数据表明，MAS-PCR 是一种快速、方便的筛查 12S rRNA 突变的方法，有助于早期发现和预防线粒体耳聋。
