非综合征型聋家系SLC26A4基因复合杂合突变

目的 研究1例前庭导水管扩大患者的遗传方式和基因突变位点。方法 以1例临床诊断为前庭导水管扩大的患者及其健康的父母为研究对象,采集其静脉血,使用全外显子测序技术检测先证者的遗传序列,进行生物信息学分析,锁定该患者可能的致病基因及突变位点,并进一步采用Sanger测序法对其父母进行相关突变位点验证,最终确定该患者的致病基因;通过单核苷酸多态性位点分析、氨基酸保守性分析及氨基酸序列分析等手段,分析复合杂合突变的致病机制,绘制突变的遗传系谱。结果 该患者致病突变定位于7q31的SLC26A4基因,由c.919-2A>G、c.1746del G以及c.563T>C 3个位点组成的复合杂合突变。SLC26A4基因的c.919-2A>G突变遗传自其听力正常的父亲,而SLC26A4基因的c.1746del G和c.563T>C突变均遗传自其听力正常的母亲。结论 先证者携带的SLC26A4基因的3个突变位点均是明确的与听力损伤相关的隐性疾病突变位点。因此,推测SLC26A4基因的上述3个突变以某种复合杂合的形式导致受检者患病。     

OTOGL复合杂合突变致常染色体隐性遗传非综合征型聋的遗传及听力表型分析

目的 探寻1个中国汉族非综合征型遗传性聋家系的致病原因。方法 收集该家系临床资料，采集静脉血后抽提DNA,通过Sanger测序对三大常见耳聋基因(GJB2、SLC26A4、线粒体DNA 12SrRNA)全序列进行筛查以排除致病突变，通过靶向捕获二代测序对目前所有已知耳聋基因进行检测并寻找该患者的可疑致病基因，并通过Sanger测序对变异进行验证。结果 该家系中先证者听力表型为中度听力障碍，其姐姐为中重度听力障碍，其父母听力正常，对先证者进行三大耳聋基因筛查未见可疑致病突变，通过靶向捕获二代测序及Sanger测序验证发现OTOGL基因截短类型的复合杂合突变是该家系高度可能的致病原因，先证者及其姐姐均携带OTOGL基因c.2833C>T(p.Arg945*)/c.6467C>A(p.Ser2156*)复合杂合突变，分别来自其父母。根据美国医学遗传与基因组学会(American College of medical genetics and genomics, ACMG)遗传变异分类标准与指南，c.2833C>T(p.Arg945*)与c.6467C>A(p.Ser2...     

一个中国耳聋近亲婚配家系TMIE基因致病性新突变

目的对一个有近亲婚配史的常染色体隐性遗传性聋家系进行遗传学分析,明确其病因,为该家系的遗传咨询提供依据。方法首先,收集该家系成员的临床资料及外周血血样;其次,运用耳聋基因芯片对先证者进行167个已知耳聋基因检测;最后,对检出的致病变异在家系中进行Sanger测序验证。结果该家系先证者及其父亲为极重度感音神经性聋患者,均存在TMIE基因c.458_462delAAGGA纯合变异,母亲为c.458_462delAAGGA杂合变异。家系内该变异与耳聋表型共分离,此变异经查阅文献和数据库未见致病性报道。结论 TMIE基因c.458_462delAAGGA纯合变异为该家系耳聋患者的致聋遗传因素,并通过本研究首次明确了此变异为致病性变异。     

一个常染色体显性遗传性聋家系致病基因鉴定

目的分析常染色体显性遗传性聋家系的听力学及遗传学特征,利用高通量测序和连锁分析技术进行致病基因鉴定。方法采集一个常染色体显性遗传性非综合征型聋家系患者的临床资料,进行耳聋表型和遗传方式的判定并绘制家系图,提取家系成员外周血DNA,首先利用耳聋相关基因靶向测序,对家系先证者进行162个已知耳聋基因的筛查,然后采用全外显子组测序和连锁分析相结合的方法继续寻找致病基因,筛选出候选基因变异位点在家系中进行验证,以明确该家系致病原因。结果该耳聋家系来自河南省,编号为HBSY-012,现存三代共34人,14人诊断为感音神经性聋,为常染色体显性遗传模式,耳聋者发病年龄5~7岁,早期表现为高频听力下降,随年龄增长迅速发展为全频受累的重度或极重度感音神经性聋。对先证者进行已知162个耳聋基因筛查未发现致病突变,家系连锁分析将致病基因定位于第9号染色体q31.1-q31.3区间内(最大LOD值3.6076)。全外显子组测序数据分析显示在连锁分析定位的区间内未发现候选变异,在区间以外筛选出4个候选基因变异位点,候选变异为ANKMY2基因NM_020319c.822_826del、DDX49基因NM_019070c.341C>T、DEFB129基因NM_080831c.284G>T以及EVI5基因NM_005665c.2399C>T,并对4个候选基因变异位点进行家系验证,结果提示都不是该家系的致病突变。结论该常染色体显性遗传非综合征型聋家系连锁分析将致病基因定位于第9号染色体q31.1-q31.3区间内。耳聋相关基因靶向测序和全外显子组测序均未发现致病突变,考虑该家系致病原因可能为基因的非编码区域的突变或者罕见的CNV/SV所致。     

一个非综合征型聋家系的遗传学分析及产前诊断

目的 对一个遗传性聋家系进行致病基因鉴定、遗传咨询和产前诊断。方法 运用目标区域捕获测序检测一个非综合征型聋家系遗传学病因,对检出的致病突变进行Sanger测序验证,结合STR检测技术对该家系行产前诊断。结果 一个家系两代人(Ⅰ:2、Ⅱ:2、Ⅱ:3)均为遗传性聋,但病因不同,先证者(Ⅰ:2)是SLC26A4基因C.919-2A>G纯合突变导致,两个异卵双胞胎女儿(Ⅱ:2、Ⅱ:3)耳聋病因是MYO15A基因c.5062＿5063delCT/c.7396-1G>A复合杂合突变。先证者孕期胎儿产前诊断结果显示耳聋风险低,出生后复查与产前诊断一致,并顺利通过新生儿听力筛查。结论 本研究明确了该非综合征型聋家系的基因型,首次明确了MYO15A基因c.5062＿5063delCT突变为致病性变异,拓展了MYO15A基因致病突变谱。     

耳聋基因panel在耳聋基因诊断中的临床应用

目的探讨耳聋基因panel技术在耳聋患者基因诊断中的应用。方法40例耳聋患者首先采用荧光定量PCR结合Sanger测序法检测4个常见耳聋基因的25个位点突变,初检结果单杂合致病突变者行耳聋基因单基因测序或耳聋基因panel检测;初检结果未发现耳聋基因致病性突变者直接行耳聋基因panel检测。16例患者行父母耳聋基因溯源验证。结果40例患者中,耳聋基因筛查检出GJB2基因纯合或复合杂合突变8例、单杂合突变2例,SLC26A4基因纯合突变1例、单杂合突变2例。4例单杂合突变检出者接受进一步的耳聋单基因或耳聋基因panel测序,其中2例分别检出GJB2基因c.235delC/c.610delC及c.235delC/c.109G>A复合杂合突变,2例检出SLC26A4基因c.919-2A>G/c.1548_1549insC复合杂合突变。27例初检结果阴性患者接受了进一步的耳聋基因panel检测,检出GJB2基因c.109G>A纯合突变4例和c.571T>C/c.G109A复合杂合突变1例,MYO7A基因c.397dupC/c.3484A>T复合杂合突变1例,MYO15A基因c.4779+2T>C/c.5008-2A>G复合杂合突变1例,ACTG1基因c.118C>T单杂合突变1例,CDH23基因c.1765G>A/c.6504T>A及c.6049G>A/c.7225-1G>A复合杂合突变各1例。在16例行父母溯源的耳聋患者中,15例患者耳聋基因突变分别遗传自其父母。结论对于耳聋基因热点突变检测结果阴性的耳聋患者,应用耳聋基因panel能有效提高遗传性致病基因检出效率,为其遗传学诊断和临床治疗提供依据。     

两个耳聋家系TMPRSS3基因突变分析及产前诊断

目的对两个耳聋家系进行遗传性耳聋基因突变检测,为家系遗传咨询与产前诊断提供参考。方法2018年3—12月,郑州大学第一附属医院遗传与产前诊断中心应用二代测序技术对两个家系患儿进行耳聋基因检测(包含168个已知致病基因,包括核基因、相关线粒体区域及miRNA),并对可疑基因在患儿及家系成员中进行Sanger双向测序验证,确定致病突变后,对两个家系的高危胎儿进行产前诊断。结果家系1患儿检测到TMPRSS3基因c.432delA和c.617-2_617-1insTC复合杂合突变,家系2患儿检测到TMPRSS3基因c.271C>T(p.R91X)和c.147dupT复合杂合突变,两家系患儿父母均为携带者。产前诊断结果显示两家系胎儿均只携带1个杂合突变。随访至2019年8月,两家系二胎分别为15月龄和13月龄,听力未见异常。结论TMPRSS3基因突变可能是两个耳聋家系的致病基因,用二代测序技术可以高效、经济准确地对遗传性耳聋患者进行基因诊断,为家系遗传咨询和产前诊断提供参考。     

外显子组测序一个常染色体显性遗传非综合征型聋家系致病基因ACTG1

目的分析一个遗传性非综合征型耳聋家系的临床听力学特征,应用全外显子组测序技术鉴定该家系的致聋基因。方法通过家系调查,对一个感音神经性聋家系进行临床资料的收集、整理及临床听力学和遗传学特征分析,对家系成员进行调查并绘制系谱图。对2名患病的家系成员进行全外显子组测序确定候选基因,对所有家系成员进行候选基因突变的Sanger测序验证。结果该耳聋家系遗传方式为常染色体显性遗传,患者表现为迟发性、渐进性、早期以高频下降为主的听力损失,全外显子组测序提示已知耳聋基因ACTG1第4外显子存在c.364A>G杂合突变,并引起编码蛋白p.I122V的改变,该位点在多物种之间保守,Sanger测序确认该位点突变与此家系耳聋表型共分离。ACTG1编码的γ-肌动蛋白I122位点的改变可能破坏肌动蛋白纤维的组装,从而影响内耳毛细胞的静纤毛结构和功能。结论该耳聋家系为常染色体显性遗传方式,已知耳聋基因ACTG1第4外显子c.364A>G（p.I122V）突变为该耳聋家系的致病原因。     

一个非综合征性遗传性耳聋家系中MYO7A基因的突变分析

目的:对一个非综合征性遗传性耳聋家系进行遗传学分析,查找该疾病的致聋性突变.方法:对该耳聋家系成员进行病史采集、听力、视力、基因组全外显子测序法检查分析,Sanger测序验证.结果:在MYO7A基因发现两个突变位点,分别为c.1183C＞T、1496T＞C,其中c.1183C＞T有少量国外文献报道,1496T＞C为新发...     

非综合征型聋患者及家庭成员耳聋基因MYO15A检测及其产前诊断意义北大核心CSCD

目的分析2例汉族非综合征型聋(nonsyndromic sensorineural hearingloss,NSHL)患者及家庭成员中耳聋基因MYO15A的突变位点,探讨MYO15A基因检测用于产前诊断的可行性。方法采集2例汉族非综合征型感音神经性聋患儿(均为男性,年龄分别为2岁8个月和3岁6个月)及两个家庭(编号为NSHL-01和NSHL-02)成员血样并记录临床资料。应用芯片捕获高通量测序(targeted genomic capturing and next-generation sequencing,targeted DNA-Hiseq)对2例NSHL患儿进行127个耳聋基因检测,获得变异序列后,针对所检出变异序列对家庭成员和健康对照个体的MYO15A基因序列进行变异验证分析,确定致病性突变后,使用sanger测序法对NSHL-02家庭中的高危胎儿进行孕中期产前诊断。结果在NSHL-01家庭的患儿中检测出MYO15A基因复合杂合突变,即:内含子18亚区c.5134-1G>A(p.-)杂合突变和外显子20亚区c.5324A>C(p.Gln1775Pro)杂合突变,本地收集的200例正常测序样本中无关于此SNP的频率信息;患儿的父亲携带c.5134-1G>A杂合突变,而患儿的母亲携带c.5324A>C杂合突变。在NSHL-02家庭的患儿检出MYO15A基因复合杂合突变,第二外显子c.374delG(Arg125ArgfsX319)杂合突变和外显子56亚区c.9358C>T(p.Gln3120Ter)杂合突变,本地收集的200例正常测序样本中无关于此SNP的频率信息;患儿的父亲携带c.9358C>T杂合突变,而患儿的母亲携带c.374delG杂合突变;该家庭高危胎儿携带c.9358C>T杂合突变,不携带c.374delG杂合突变,出生后表型正常。结论 MYO15A基因内含子18亚区c.5134-1G>A杂合突变和外显子20c.5324A>C杂合突变,及第二外显子c.374delG杂合突变和外显子56亚区c.9358C>T杂合突变是2个NSHL家庭的致病原因,芯片捕获高通量测序及数据分析技术可对2个NSHL家庭进行有效的基因诊断,结合sanger技术可进行产前诊断。     

A novel recessive truncating mutation in MYO15A causing prelingual sensorineural hearing loss

Hearing loss (HL) is one of the most common human defects which affects millions of people globally. The identification of deafness-related genes or loci may facilitate basic and clinical translational research on this disorder. Here, we investigated a Chinese family with autosomal recessive non-syndromic hearing impairment. Using targeted massively parallel sequencing, we identified a novel homozygous mutation, c.3525_3526insA and p.Q1175fsX1188 (NM_016239), in exon 2 of MYO15A. Sanger sequencing confirmed that affected siblings were homozygous for the mutation, whereas both normal hearing parents were heterozygous. The mutation was absent in 96 healthy controls and public databases. The insertion leads to a frameshift and a truncated form of the protein, resulting in the pathogenic effect of hearing loss for the patients. Mutations in exon 2 of MYO15A may cause a less severe phenotype, facilitating the rapid identification of mutations in exon 2 among the 66 exons when linkage of less severe hearing loss to Deafness, Autosomal Recessive 3 (DFNB3) is detected. Our data provide additional molecular information for establishing a better genotype–phenotype understanding of DFNB3.     

Compound heterozygous MYO7A mutations segregating Usher syndrome type 2 in a Han family

ObjectiveIdentification of rare deafness genes for inherited congenital sensorineural hearing impairment remains difficult, because a large variety of genes are implicated. In this study we applied targeted capture and next-generation sequencing to uncover the underlying gene in a three-generation Han family segregating recessive inherited hearing loss and retinitis pigmentosa.MethodsAfter excluding mutations in common deafness genes GJB2, SLC26A4 and the mitochondrial gene, genomic DNA of the proband of a Han family was subjected to targeted next-generation sequencing. The candidate mutations were confirmed by Sanger sequencing and subsequently analyzed with in silico tools.ResultsAn unreported splice site mutation c.3924+1G > C compound with c.6028G > A in the MYO7A gene were detected to cosegregate with the phenotype in this pedigree. Both mutations, located in the evolutionarily conserved FERM domain in myosin VIIA, were predicted to be pathogenic. In this family, profound sensorineural hearing impairment and retinitis pigmentosa without vestibular disorder, constituted the typical Usher syndrome type 2.ConclusionIdentification of novel mutation in compound heterozygosity in MYO7A gene revealed the genetic origin of Usher syndrome type 2 in this Han family.     

Compound heterozygous GJB2 mutations associated to a consanguineous Han family with autosomal recessive non-syndromic hearing loss

Conclusion: This study demonstrates that the gap junction protein beta-2 gene (GJB2) p.R32C and p.L79Cfs*3 variants are associated to a consanguineous family with autosomal recessive non-syndromic hearing loss (ARNSHL). The p.R32C variant is found for the first time in the NSHL patients of Han Chinese origin. The finding sheds new light on the accurate genetic diagnosis and counseling for the family. Objective: ARNSHL is a highly heterogeneous genetic disease. ARNSHL usually displays non-progressive congenital or pre-lingual deafness. In this study, the aim is to detect the disease-causing mutation(s) in a Han family with ARNSHL. Methods: A consanguineous Han family with ARNSHL was enrolled. Two hundred ethnicity-matched unrelated subjects without any hearing impairments were used as normal controls. Exome sequencing and Sanger sequencing were applied to identify the causative mutation in the ARNSHL family. Results: Compound heterozygous variants c.94C?>?T (p.R32C) and c.235delC (p.L79Cfs*3) in the GJB2 gene were identified in the two patients of the ARNSHL family, and the heterozygous GJB2 c.94C?>?T and c.235delC variants were identified in his unaffected father and mother, respectively. The two variants in the GJB2 gene were absent in the 200 unrelated controls.     

Identification of a MYO7A mutation in a large Chinese DFNA11 family and genotype–phenotype review for DFNA11

Background: The molecular and genetic research showed the association between DFNA11 and mutations in MYO7A. This research aimed to identify a MYO7A mutation in a family with nonsyndromic autosomal dominant hearing loss.

Methods: We have ascertained one large multigenerational Chinese family (Z029) with autosomal dominant late-onset progressive non-syndromic sensorineural hearing loss. Genome-wide linkage analysis of the family mapped the disease locus to the DFNA11 interval, where the MYO7A was considered as a candidate gene. Sequencing of the PCR products was carried out for each sample. One hundred and fifty one control subjects with normal hearing functions were also evaluated.

Results: The pathogenic mutation (c.2011G>A) was identified in the family. This mutation co-segregated with hearing loss in this family. No mutation of MYO7A gene was found in the 151 controls.

Conclusions: The missense mutation of MYO7A is identified in the family displaying the pedigree consistent with DFNA11. We not only examined the clinical and genetic characteristics of the family, but also provided a basis for genetic counseling. We also summarized and analyzed the phenotypes and genotypes of all DFNA11 families, four of nine are Chinese families, suggesting that MYO7A mutations are not rare. Therefore, we should pay more attention to Chinese patients.     

Novel OTOF gene mutations identified using a massively parallel DNA sequencing technique in DFNB9 deafness

Abstract

Objectives: This study examined the causative genes in patients with early-onset hearing loss from two Chinese families.

Method: Massively parallel sequencing, designed to screen all reported genes associated with hearing loss, was performed in a large number of Chinese individuals with hearing loss. This study enrolled patients with the same OTOF mutation and analyzed their phenotype–genotype correlations.

Results: Three novel OTOF mutations (NM_001287489) [c.1550T?>?C (p.L517P), c.5900_5902delTCA (p.I1967del), and c.4669_4677delCTGACGGTG (p.L1557-V1559del)] were found to be the cause of hearing loss in five patients. In family AH-890, the affected subject homozygous for p.L517P presented with profound hearing loss, while the affected sisters compound heterozygous for p.L517P and p.I1967del had mild-to-moderate hearing loss. The patient with hearing loss in family SD-345 was found to be compound heterozygous for p.L517P and p.L1557-V1559del.

Conclusion: Three presumably pathogenic mutations in the OTOF gene were detected for the first time, including the first pathogenic mutation detected in the TM domain. In addition to expanding the spectrum of OTOF mutations resulting in DFNB9, our findings present the diversity of its clinical presentation and indicate that MPS is an efficient approach to identify the causative genes associated with hereditary hearing loss.     

Allelic heterogeneity among Iranian DFNB7/11 families: report of a new Iranian deaf family with TMC1 mutation identified by next-generation sequencing

Conclusion: Co-segregation of c.2030T>C mutation with hearing loss in an Iranian family and absence of this mutation in 100 Iranian controls confirms the pathogenicity of this mutation. Allelic heterogeneity among Iranian DFNB7/11 families has been shown by the identification of six different mutations in eight families. Objectives: Transmembrane channel-like 1 (TMC1) gene encodes an integral membrane protein such that its mutations can cause DFNB7/11 hearing loss. To date, several TMC1 mutations have been reported from Iran. Here we report a new DFNB7/11 Iranian family with an unreported TMC1 mutation in Iran. Methods: A total of 66 genes related to hearing loss were analyzed using the OtoSCOPE platform in an affected member of an Iranian deaf family (Irn-Deaf-6866). Sanger sequencing was performed to confirm next-generation sequencing findings. Results: A mutation, c.2030T>C, was identified in exon 21 of the TMC1 gene in the investigated member of the family. Sequencing results in all members of the family confirmed association of this mutation with hearing loss. None of 100 ethnically matched healthy controls had this mutation.     

A novel mutation in PAX3 associated with Waardenburg syndrome type I in a Chinese family

Conclusion The novel compound heterozygous mutation in PAX3 was the key genetic reason for WS1 in this family, which was useful to the molecular diagnosis of WS1. Purpose Screening the pathogenic mutations in a four generation Chinese family with Waardenburg syndrome type I (WS1). Methods WS1 was diagnosed in a 4-year-old boy according to the Waardenburg syndrome Consortium criteria. The detailed family history revealed four affected members in the family. Routine clinical, audiological examination, and ophthalmologic evaluation were performed on four affected and 10 healthy members in this family. The genetic analysis was conducted, including the targeted next-generation sequencing of 127 known deafness genes combined with Sanger sequencing, TA clone and bioinformatic analysis. Results A novel compound heterozygous mutation c.[169_170insC;172_174delAAG] (p.His57ProfsX55) was identified in PAX3, which was co-segregated with WS1 in the Chinese family. This mutation was absent in the unaffected family members and 200 ethnicity-matched controls. The phylogenetic analysis and three-dimensional (3D) modeling of Pax3 protein further confirmed that the novel compound heterozygous mutation was pathogenic.     

Identification of a de novo mutation of SOX10 in a Chinese patient with Waardenburg syndrome type IV

ObjectivesWaardenburg syndrome is a rare genetic disorder, characterized by the association of sensorineural hearing loss and pigmentation abnormalities. Four subtypes have been classified. The present study aimed to analyze the clinical feature and investigate the genetic cause for a Chinese case of Waardenburg type IV (WS4).MethodsThe patient and his family members were subjected to mutation detection in the candidate gene SOX10 by Sanger sequencing.ResultsThe patient has the clinical features of WS4, including sensorineural hearing loss, bright blue irides, premature graying of the hair and Hirschsprung disease. A novel heterozygous frameshift mutation, c.752_753ins7 (p.Gly252Alafs*31) in the exon 5 of SOX10 was detected in the patient, but not found in the unaffected family members and 100 normal controls. This mutation results in a premature stop codon 31 amino acid downstream.ConclusionsThe novel mutation c.752_753ins7 (p.Gly252Alafs*31) arose de novo and was considered as the cause of WS4 in the proband. This study further characterized the molecular complexity of WS4 and provided a clinical case for genotype-phenotype correlation studies of different phenotypes caused by SOX10 mutations.     

Detecting novel mutations and combined Klinefelter syndrome in Usher syndrome cases

Background: Usher syndrome (USH) is an autosomal recessive disease characterized by hearing loss, vision loss, and occasionally vestibular dysfunction. Klinefelter syndrome (KS) is an X chromosome polyploidy characterized by one or more additional X chromosomes in males. To date, there has been no report of USH combined with KS.

Objectives: This study examined the causative genes in three Chinese probands with congenital hearing loss.

Material and methods: Targeted next-generation sequencing (NGS) was performed to identify mutations in three probands with hearing loss. Low-coverage whole-genome sequencing (WGS) analysis of aneuploidy was used to verify the chromosome aneuploidy.

Results: Four novel MYO7A mutations were identified in two USH1 probands who were initially diagnosed with nonsyndromic hearing loss until the onset of vision loss. Another case was initially diagnosed with nonsyndromic hearing loss and USH2 and KS were discovered incidentally after the genetic analysis.

Conclusions: Our findings expand the mutation spectrum of MYO7A. This is also the first report of concomitant USH and KS. Genetic testing can help with clinical management, particularly if an unrecognized syndromic disorder is identified before the onset of additional symptoms. A clinical genetic evaluation is recommended as part of the diagnostic work-up in congenital hearing loss.