The analysis of mutations in non-syndromic deafness gene SLC26A4 by next generation sequencing technology
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摘要: 目的:分析芯片捕获高通量测序技术(targeted DNA-Hiseq)在非综合征聋患儿中的应用,分析SLC26A4基因的新突变及突变谱,为临床开展基因诊断及遗传咨询提供依据。方法:应用飞行质谱方法对57例资料完整的非综合征聋患儿进行SLC26A4基因高发位点c.919-2A>G检测,c.919-2A>G纯合突变3例,c.919-2A>G杂合突变7例。再应用targeted DNA-Hiseq对c.919-2A>G纯合突变以外的54例患儿进行非综合征聋81个基因测序,包括SLC26A4基因,并应用桑格法通过父母DNA进行验证。结果:57例患儿中15例(26.32%)发现SLC26A4基因突变,其中致病突变中c.919-2A>G纯合突变3例,c.754T>C(p.Ser252Pro)纯合突变1例,复合杂合突变6例,11例临床均已诊断为大前庭水管综合征(LVAS),并已经进行耳蜗植入或佩戴助听器。其中1例LVAS患儿复合杂合突变为c.2168A>G(p.His723Arg)和c.1545-1546insC(p,Phe515PhefsX12),c.2168A>G为致病突变,而c.1545-1546insC为疑似致病突变,推测复合杂合突变c.2168A>G和c.1545-1546insC为致聋原因,因此SLC26A4基因突变导致耳聋占19.30%(11/57)。单杂合突变4例,临床均未诊断为LVAS。结论:SLC26A4双等位基因突变可导致LVAS,其中c.919-2A>G突变为热点突变,通过targeted DNA-Hiseq发现SLC26A4基因新致病突变c.1545-1546insC。Abstract: Objective: To analogize the distribution of non-syndromic deafness gene SLC26 A4 mutation and to characterize clinical profiles in patients with SLC26 A4 mutation in order to understand their hereditary etiologies and provide evidence for deafness screening and accurate genetic counseling. Method: SLC26 A4 gene was first analized by MALDI-TOF-MS technology to detect the hot mutation c.919-2 A>G in 57 cases. There were 3 cases with homozygous mutation and 7 cases with heterozygous mutation. Then 54 cases except for 3 cases with homozygous mutation were analyzed by targeted genomic capturing and next generation sequencing technologies(targeted DNA-Hiseq), 81 non-syndromic deafness genes and the chondiogene was designed to all their exons and their flanking intron(±10 bp) sequences. Sanger sequencing was used to confirm the variant by analyzing the DNAs sequences. Result: The carrying rates of SLC26 A4 gene in the deafness were 26.32%, but SLC26 A4 homozygous genes and compound heterozygous genes were 19.30%. They included 3 cases with c.919-2 A>G and 1 case with c.754 T>C pathogenic homozygous mutations. While in 7 cases with compound heterozygous there were 6 cases with two pathogenic mutation, there was 1 case with c.2168 A>G pathogenic mutation the other likely pathogenic mutation c.1545-1546 insC. The 11 cases all were diagnosed large vestibular aqueduct syndrome(LVAS). There were 4 cases with heterozygous that were not found large vestibular aqueduct.Conclusion: Pathogenic mutation of SLC26 A4 is closely related to clinical phenotype of LVAS. The hot pathogenic mutation was c.919-2 A>G of SLC26 A4 gene. The next generation sequencing technology is available for the diagnosis of inherited hearing loss especially for LVAS.
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