先天性外中耳畸形(14)——遗传学和表观遗传学研究进展

1 .2 .3 鳃-耳-肾谱系疾病(BORSD ) BORSD (OMIM 113650)是一类由于胚胎发育时期基因突变导致鳃裂、耳及肾脏发育异常的单基因遗传病,发病率约1/40000 ,30％ ～60％ 的BORSD患者伴有外中耳畸形[1 ] ,呈常染色体显性遗传.具有高度的临床表型和基因型异质性,合并泌尿系统异常者...     

鳃-耳综合征一家系临床表型及遗传学特征分析

目的探讨一个鳃-耳综合征家系的表型特征,进行候选致病基因的突变筛查。方法经知情同意,对调查对象进行全身检查以及听力学和颞骨CT评估,获得血样标本;整理分析家系资料并绘制系谱图;用基因组DNA提取试剂盒提取外周血DNA,进行鳃-耳-肾综合征相关基因EYA1、SIX1和SIX5全编码外显子的序列分析。结果该家系共4代31人,7人具有鳃-耳-肾综合征相关症状,系谱分析符合常染色体显性遗传特征。6名患者主诉听力下降,为最常见临床表现,其它症状有耳前瘘管2人次、鳃裂瘘3人次和耳廓畸形4人次,均无肾脏畸形表现。2名患者纯音听力图示双耳混合性聋,颞骨CT检查见中耳和内耳发育异常,候选致病基因筛查均检测到EYA1 c.922C>T突变。结论该家系表型特征符合鳃-耳综合征诊断,但家系内患病个体间临床表现具有异质性。EYA1 c.922C>T突变是本家系致病的主要分子基础。     

鳃-耳-肾综合征一例

鳃-耳-肾综合征(branchio-oto-renal syndrome)是一种少见的常染色体显性遗传性疾病,主要表现为听力下降、耳前瘘管、鳃裂发育异常、肾发育不良等.新生儿发病率为1/40 000,在重度聋儿中占2%[1].国外对该病的临床和基因学研究已较深入,但国内仅见1例报道[2].现将作者收治的1例患儿报告如下,以加强对该病的认识.     

鳃裂-耳-肾综合征

鳃裂 -耳 -肾综合征 (Ｂｒａｎｃｈｉｏ -ｏｔｏ -ｒｅｎａｌｓｙｎｄｒｏｍｅ,ＢＯＲ)系因第一、二鳃弓发育异常、听力障碍、泌尿系统畸形而得名。ＢＯＲ是一种罕见的常染色体显性遗传疾病 ,发病率为 1:40 0 0 0 ,在深度聋儿中占 2 % [1] 。 1975年Ｍｅｌｎｉｃｋ首次报道一家系表现杯状耳、耳前凹、混合性聋、鳃裂瘘管、双肾收集系统畸形。此后陆续有关于该病的报道。近年随着基因分子生物学的发展 ,定位克隆了ＢＯＲ的致病基因 ,即ＥＹＡ1基因 ,为ＢＯＲ的诊断提供了更直接的方法。1　临床表现和实验室检查1 1　耳异常 :耳部异常包括耳发…     

耳蜗神经发育不良听神经病谱系障碍患者听力学分析

目的分析中国听神经病谱系障碍患者蜗神经的发育情况,进一步探讨中国听神经病谱系障碍患者的相关影像学特征。方法本研究以19例行内听道斜矢状位高分辨核磁共振成像的听神经病谱系障碍患者为研究对象,进行详细的病史采集和听力学检测。纯音测听检测、声导抗检测、听性脑干反应、DPOAE检测、言语识别率检测等,回顾性分析听神经病谱系障碍患者的蜗神经影像学特征,并探讨蜗神经发育异常患者的听力学特征。结果本研究的19例听神经病谱系障碍患者中,共发现4例蜗神经发育异常的患者,所占比例为21.05(4/19)。4例患者在内听道斜矢状位MRI上均表现为双侧蜗神经细小。其中,2例患者有耳聋家族史,1例患者伴有共济失调障碍。4例蜗神经发育异常的患者听力曲线类型各异:2例患者表现为全频中度下降的平坦型听力曲线,1例表现为中重度低频上升型听力曲线,另外1例表现为中重度的高频下降型听力曲线。4人(8耳)的言语识别率均较差,除1耳外,其余7耳的言语识别率均低于40%。结论对于听神经病谱系障碍的患者,若条件允许的情况下,应常规行内听道斜矢状位高分辨核磁共振成像,以评价蜗神经粗细及发育情况,对于了解听神经病谱系障碍患者的病变部位和病因。     

先天性双侧第二鳃裂瘘管误诊1例

鳃裂畸形属于先天性疾病,它是由胚胎发育过程中鳃沟与咽囊发生异常穿破或未完全闭合而形成的,可表现为颈侧部的囊肿、瘘管或窦道,临床上以第二鳃裂发育异常最为多见,由于其发病率低,极易导致误诊。王绍忠等[1]报道误诊率接近20％。2012年8月笔者收治1例双侧第二鳃裂瘘管患者,现报告如下。     

一个鳃-耳-肾综合征家系的EYA1基因新致病性变异及诊断探讨北大核心CSCD

通过家系调查、临床检查和遗传学特征分析,对一个鳃-耳-肾综合征家系的临床表型及致病原因进行系统研究。该家系表现为常染色体显性遗传,4位先证者均表现为听力损失、鳃裂瘘管、耳前瘘管、肾异常中的两种及以上的混合症状,症状轻重不等。遗传性耳聋基因芯片检测未发现常见的耳聋基因突变,sanger法基因检测结果显示4位先证者的EYA1基因c.889C>T(p.R297X)突变,为无义突变且均为杂合变异,根据美国医学遗传学与基因组学学会(American College of Medical Genetics and Genomics,ACMG)指南初步判定为致病性变异,现结合文献报道如下。     

一个鳃-耳-肾综合征家系EY A1基因新致病性变异

目的 研究一个鳃-耳-肾综合征(branchio-oto-renal,BOR)家系的临床表型及遗传学特征.方法 通过家系调查、临床检查和遗传学特征分析,对一个鳃-耳-肾综合征家系的临床表型及致病原因进行系统研究,提取家系成员的外周血DNA,采用遗传性耳聋基因芯片进行最常见的GJB2(135 del G、176 del ...     

双耳前瘘管伴一侧鳃裂囊肿1例报告

先天性鳃裂瘘管或囊肿由胚胎时鳃裂残余发展形成,第一鳃裂瘘管或囊肿是由第一鳃沟发育异常所致,临床少见,Ａｒｎｏｔ（１９７１年）将此病分两型, Ｉ型外孔位于耳前或耳后,瘘道与外耳道平行,但不通外耳道内,故囊肿、窦道多在面神经外上方,现将遇到一例双耳前瘘管伴右侧第一鳃裂囊肿病人,报告如下。 患者,男性,１８岁,因双耳前反复肿痛十余年,加重一周入院,患者幼年即出现双耳前肿痛反复发作以右侧较甚。一直拟“双耳前瘘管”保守治疗。一周前症状复发,门诊予补液抗炎及切开排脓治疗后收住入院,检查：双耳廓正常,耳屏前上方…     

先天性外中耳畸形

先天性耳畸形可涉及外耳（耳廓）、中耳和内耳,可单独发生或联合出现,是耳科常见的出生缺陷,本期讨论的重点是先天性外中耳畸形。源于第、鳃弓及第鳃沟发育不良,临床主要表现为耳廓畸形影响容貌;外耳道狭窄或闭锁、中耳及听骨链发育不良或畸形引起传导性聋影响听觉及言语发育。部分患者是综合征的表现之一,     

The branchio-oto-renal syndrome (report of two family groups)

The major features of the Branchio-Oto-Renal syndrome (BOR syndrome), an autosomal dominant disorder, are branchial remnants, ear anomalies, deafness and renal dysplasia. We report two family groups affected by the BOR syndrome: in two-thirds of the affected children renal abnormalities led to severe renal insufficiency in early life. The necessity for a meticulous search for renal anomalies in individuals with aural and/or branchial abnormalities is emphasized. In affected families, genetic counselling is suggested.     

Phenotypic consequences in a Japanese family having branchio-oto-renal syndrome with a novel frameshift mutation in the gene EYA1

Branchio-oto-renal (BOR) syndrome is an autosomal dominant inherited disorder characterized by malformations of the ear associated with hearing impairment, branchial fistulae or cysts, and renal malformations. Mutations in the gene EYA1 have been found to be responsible for BOR syndrome in approximately 40% of the subjects. Here we report a Japanese family with BOR syndrome associated with a frameshift mutation in EYA1. This mutation, 1667-1668insT, has not been previously reported and is also the first frameshift mutation in exon 16 of this gene. We describe the detailed clinical features and medical highlights of the family members, and based on their clinical histories we propose that genetic testing for EYA1 mutations would contribute to the diagnosis of BOR syndrome, facilitate genetic counseling for recurrence, give precautions regarding possible renal disorders later in life, and impact the consideration of surgical intervention for middle ear anomalies.     

Novel EYA1 mutation in a Korean branchio-oto-renal syndrome family

Branchio-oto-renal (BOR) syndrome is an autosomal dominant disorder that is characterized by branchial cysts or fistulae, external ear malformations and/or preauricular pits, hearing loss and renal anomalies. Recent advances in molecular genetics have shown a human homologue of the Drosophila 'eyes absent' gene (EYA1) on chromosome band 8q13.3 to be the most common cause of BOR syndrome. Several mutations have been identified in the EYA1 gene in patients with BOR syndrome worldwide. Here, we report a second Korean family with BOR syndrome with a novel nonsense EYA1 mutation.     

Examination of Nasopharyngeal Epithelium with Contact Endoscopy

Branchio-oto-renal (BOR) syndrome is an autosomal dominant inherited disorder characterized by malformations of the ear associated with hearing impairment, branchial fistulae or cysts, and renal malformations. Mutations in the gene EYA1 have been found to be responsible for BOR syndrome in approximately 40% of the subjects. Here we report a Japanese family with BOR syndrome associated with a frameshift mutation in EYA1. This mutation, 1667-1668insT, has not been previously reported and is also the first frameshift mutation in exon 16 of this gene. We describe the detailed clinical features and medical highlights of the family members, and based on their clinical histories we propose that genetic testing for EYA1 mutations would contribute to the diagnosis of BOR syndrome, facilitate genetic counseling for recurrence, give precautions regarding possible renal disorders later in life, and impact the consideration of surgical intervention for middle ear anomalies.     

Identification of a novel mutation in the EYA1 gene in a Korean family with branchio-oto-renal (BOR) syndrome

The branchio-oto-renal (BOR) syndrome is an autosomal dominant disorder characterized by the association of branchial cysts or fistulae, external ear malformation and/or preauricular pits, hearing loss, and renal anomalies. Mutations in the EYA1 gene on the chromosome band 8q13.3, the human homologue of the Drosophila eyes absent (eya) gene, have been identified to be the underlying genetic defects of the syndrome. We found a Korean family with BOR syndrome and identified a novel insertion mutation (c.1474_1475insC; R492PfsX40) in the EYA1 gene. To the best of our knowledge, this is the first report of genetically confirmed case of BOR syndrome in Korea.     

Branchio-oto-renales Syndrom (BOR-Syndrom) Ein Dysplasiesyndrom mit Kiemenbogenanomalien, Schwerhörigkeit und Nierenerkrankung

The branchio-oto-renal syndrome (BOR syndrome) is characterized by auricular abnormalities, lateral cervical fistulas and preauricular tags. The hearing impairment may be a conductive, a sensorineural or a mixed hearing loss. The renal disease is oligomeganephronia, a bilateral, congenital renal abnormality with reduced numbers of nephrons. The BOR syndrome is an autosomal-dominant disease. An 8-year-old girl with preauricular tags, cervical fistulas and auricular abnormalities is reported upon. She has a mixed hearing loss and anomalies in the vestibular system. Renal disorders are not diagnosed. The BOR syndrome is a disorder with branchial, otologic and renal manifestations. These are usually incomplete. Less common anomalies that occur include facial nerve paralysis, lacrimal duct stenosis and other auricular abnormalities. The syndrome shows a highly variable expressivity, so that severe renal anomalies may be the limiting factor. Malformations in the head region may undergo cosmetic surgery depending on their grade and behaviour. After audiometric evaluation the hearing disorder can be well-treated with hearing aids.     

A novel splice site mutation in the EYA1 gene in a Korean family with branchio-oto (BO) syndrome

Branchio-oto-renal (BOR) and branchio-oto (BO) syndromes are autosomal dominant hereditary disorders characterized by the presence of hearing loss and branchial fistulae and cysts, with (BOR syndrome) or without (BO syndrome) renal malformations of varying degrees of severity. Mutations in the human homologous of the Drosophila eyes absent (EYA1) gene are frequently the cause of BOR/BO syndrome. Here we describe a Korean family with BO syndrome; the proband had preauricular pit, cup-shaped auricles, branchial fistula, and hearing loss, without renal involvement. Molecular genetic study revealed a novel mutation occurring in the consensus acceptor splice site of intron 8 (c.868-2A > G) in the EYA1 gene. To the best of our knowledge, this is the first report of a splice site mutation in a family with BO syndrome without renal involvement, further extending the phenotypic-genotypic heterogeneity of BOR/BO syndrome.     

A novel splice site mutation in the EYA1 gene in a Korean family with branchio-oto (BO) syndrome

Branchio-oto-renal (BOR) and branchio-oto (BO) syndromes are autosomal dominant hereditary disorders characterized by the presence of hearing loss and branchial fistulae and cysts, with (BOR syndrome) or without (BO syndrome) renal malformations of varying degrees of severity. Mutations in the human homologous of the Drosophila eyes absent (EYA1) gene are frequently the cause of BOR/BO syndrome. Here we describe a Korean family with BO syndrome; the proband had preauricular pit, cup-shaped auricles, branchial fistula, and hearing loss, without renal involvement. Molecular genetic study revealed a novel mutation occurring in the consensus acceptor splice site of intron 8 (c.868-2A > G) in the EYA1 gene. To the best of our knowledge, this is the first report of a splice site mutation in a family with BO syndrome without renal involvement, further extending the phenotypic-genotypic heterogeneity of BOR/BO syndrome.     

A family affected by branchio-oto syndrome with EYA1 mutations

Branchio-oto (BO) syndrome is complicated with congenital preauricular fistulae, branchial fistulae (cysts), and hearing loss (sensorineural, conductive or mixed). As well as branchio-oto-renal (BOR) syndrome, it is known to be an autosomal dominant hereditary disorder. Since mutations in the EYA1 gene have been identified in both BO and BOR syndromes, mutation screening of this gene has been drawing attention as a genetic test to diagnose BOR/BO syndromes. In this study, we genetically investigated the presence of EYA1 mutations in a BO syndrome family in which we observed congenital preauricular fistulae, branchial fistulae (cysts) and hearing loss in four generations. Whereas there was a variety of phenotype expressions in this family, all subjects tested had a nonsense mutation (R264X) in exon 8 of the EYA1 gene. The present report adds further examples to support the usefulness of molecular genetic testing for the diagnosis of patients with BO syndrome.     

Cochlear implantation in branchio-oto-renal syndrome — A surgical challenge

Branchio-oto-renal syndrome (Melnick-Fraser Syndrome) is a rare Autosomal Dominant disorder characterized by the syndromic association of branchial cysts or fistulae along with external, middle & inner malformations and renal anomalies. Incomplete penetrance and variable expressivity are common with the phenotypic variation ranging from mild to severe forms & consisting of various eye, ear, oral and craniofacial abnormalities. Mutations in the EYA1 gene on chromosomal site 8q13.3 are identified as the primary cause of BOR syndrome. We present a 3year old child with BOR syndrome, who came to us with bilateral low set, malformed ears & profound cochlear hearing loss along with bilateral branchial fistulae & unilateral renal agenesis. This child underwent successful cochlear implantation recently. The clinical presentation, pre-operative investigations, intra-operative findings & post-op habilitation status are presented with special highlights on the unique facial nerve course along with middle and inner ear anomalies which posed a surgical challenge during cochlear implantation.