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.     

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.     

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.     

Temporal bone findings in a family with branchio-oto-renal syndrome (BOR)

A family group with confirmed branchio-oto-renal (BOR) syndrome was investigated in this study. Computerized tomography of the temporal bones has demonstrated that the malformations of the inner ear consist of hypoplastic structural changes within the cochlea with reduced vertical diameters, and absent or hypoplastic semicircular canals and normal endolymphatic ducts. It is concluded that in the present cases, the Mondini malformation of the cochlea is not associated with the BOR syndrome.     

Clinical symptoms of branchio-oto-renal syndrome in a family with a positive test for EYA1 gene

Three families with branchio-oto-renal syndrome (BOR syndrome) were examined. In one of the families all its members with BOR syndrome had deletion of cytosine in position 759 (759delC) in DNA sequence of EYA1 gene in exone 8. Clinical characteristics of BOR syndrome in the family are given. Molecular-genetic analysis confirmed the diagnosis clinically in case of all signs of the syndrome presence among the members of the family. Rare cases of hereditary syndromes with hearing problems provide more knowledge about structure of hereditary hypoacusis forms in the population. The syndromal forms reflect a complex genetic basis of the processes of sound perception.     

Identification of a nonsense mutation in the STRC gene in a Korean family with moderate hearing loss

Hereditary hearing loss is a heterogeneous disorder that results in a common sensorineural disorder. To date, more than 150 loci and 89 genes have been reported for non-syndromic hearing loss. Next generation sequencing has recently been developed as a powerful genetic strategy for identifying pathogenic mutations in heterogeneous disorders with various causative genes. In this study, we performed targeted sequencing to identify the causative mutation in a Korean family that had moderate hearing loss. We targeted 64 genes associated with non-syndromic hearing loss and sorted the homozygous variations according to the autosomal recessive inheritance pattern of the family. Implementing a bioinformatic platform for filtering and detecting variations allowed for the identification of two variations within different genes (c.650G > A in TRIOBP and c.4057C > T in STRC). These variants were selected for further analysis. Among these, c.4057C > T (p.Q1353X) was a divergent sequence variation between the STRC gene and the STRC pseudogene. This was the critical difference that resulted in loss of the protein-coding ability of the pseudogene. Therefore, we hypothesized that the p.Q1353X variation in the STRC gene is the causative mutation for hearing loss. This result suggests that application of targeted sequencing will be valuable for the diagnosis of heterogeneous disorders.     

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.     

Mutation of the EYA1 gene in patients with branchio-oto syndrome

Branchio-oto-renal (BOR) and branchio-oto (BO) syndromes are autosomal dominant disorders, characterized by the presence of branchial, otic and renal anomalies of varying degrees of severity. We investigated the presence of EYA1 mutation in two unrelated patients with autosomal dominant hereditary deafness and congenital preauricular fistula. Case 1 had a mutation and polymorphisms, while Case 2 had polymorphisms with no mutations. In Case 1 we detected a heterozygous A-->G mutation at nucleotide 625 resulting in a serine to glycine substitution at codon 189 (S189G). The S189G mutation was not detected in 54 controls (108 alleles). Pure-tone audiometry showed bilateral mixed hearing loss of mild to moderate severity in Case 1. Case 2 had suffered from bilateral hearing loss since the age of 5 years and pure-tone audiometry showed bilateral moderate mixed hearing loss. These results suggest that the S189G mutation is a candidate mutation for 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.     

Identification of a novel mutation in the myosin VIIA motor domain in a family with autosomal dominant hearing loss (DFNA11)

We ascertained a large Italian family with an autosomal dominant form of non-syndromic sensorineural hearing loss with vestibular involvement. A genome-wide scan found linkage to locus DFNA11. Sequencing of the MYO7A gene in the linked region identified a new missense mutation resulting in an Ala230Val change in the motor domain of the myosin VIIA. Myosin VIIA has already been implicated in several forms of deafness, but this is the third mutation causing a dominant form of deafness, located in the myosin VIIA motor domain in a region never involved in hearing loss until now. A modelled protein structure of myosin VII motor domain provides evidence for a significant functional effect of this missense mutation.     

常染色体显性低频感音神经性耳聋一家系MYO7A基因一个新突变位点的鉴定分析

目的 一个命名为HB-S037的常染色体显性非综合征遗传性耳聋中国家系致病基因定位及MY07A基因突变分析.方法 通过对该家系参与连锁分析的23名成员应用Affymetrix 5.0 SNP(Single Nucleotide Polymorphisms,单核甘酸多态性)芯片进行全基因组扫描及连锁分析,致病基因的染色体定位:之后,选取微卫星标记进行精细扫描,确定候选基因,MY07A基因外显子扩增及测序.结果 应用Affymetrix 5.0 SNP芯片进行全基因组扫描及连锁分析,将HB-S037家系的致病基因初步定位于第11号染色体11q13.4-14.1之间(最大LOD值=4.346),选取初步定位区域内及附近的12个微卫星标记进行精细定位及单倍型分析,将致病基因定位于微卫星标记D11S1314和D11S4166之间的区域(最大LOD值=4.18).对定位区域内候选基因MY07A的49个外显子直接测序,在MYOTA第17外显子有一个新的突变位点c.2011G>A,该位点突变与此家系疾病表型共分离,并引起编码第671位的甘氨酸替换为丝氨酸(G671S).该位点在多物种之间保守.100个听力正常人未发现此突变.结论 HB-S037家系定位于第11号染色体的长臂11q13.4-14.1之间,致病基因为MY07A,MY07A第17外显子c.2011G>A突变引起第671位氨基酸甘氨酸替换为丝氨酸,该突变为HB-S037家系的致病突变.为MYOTA基因的一个新发现的突变位点.     

Stapes ankylosis in a family with a novel NOG mutation: otologic features of the facioaudiosymphalangism syndrome.

OBJECTIVE: To report the phenotype-genotype correlation in a Belgian family that was ascertained to have a novel missense mutation in the NOG gene mapping to chromosome 17q22. STUDY DESIGN: To describe the phenotype, a retrospective case study was performed based on the otologic, audiologic, ophthalmologic, and radiologic data of the mutation carriers of the NOG gene. SETTING: Tertiary referral center. PATIENTS: All members of a Belgian kindred who carried the novel missense mutation in the NOG gene (NOG, Trp205Cys [W205C]; 1426G>C). INTERVENTIONS: Diagnostic otologic and ophthalmologic examination, audiometric analysis, and radiologic imaging. MAIN OUTCOME MEASURES: Phenotype-genotype correlations. RESULTS: All five mutation carriers had a typical facies. Bilateral proximal symphalangism and hyperopia were present in 80%. Five of 10 ears also had progressive early-onset conductive hearing loss caused by stapes ankylosis. CONCLUSIONS: So far, 14 independent NOG mutations have been identified. The autosomal dominant disorder described in the present family was caused by a novel NOG missense mutation (NOG, Trp205Cys [W205C]; 1426G>C). The phenotype correlated well with the facioaudiosymphalangism syndrome. The mutation carriers demonstrated progressive multiple joint fusions, hyperopia, early-onset conductive deafness, and a typical facies.     

A mutation in Wolfram syndrome type 1 gene in a Japanese family with autosomal dominant low-frequency sensorineural hearing loss

Conclusion. Our findings suggest that Wolfram syndrome type 1 gene (WFS1) mutation is an important cause of autosomal dominant low-frequency sensorineural hearing loss (LFSNHL) in Japan. Objective. DFNA6/14 is caused by a heterozygous mutation of WFS1 and is a common cause of autosomal dominant LFSNHL among populations in both Europe and the US. The purpose of this study was to investigate WFS1 mutations among Japanese patients whose phenotypes were consistent with those of DFNA6/14. Material and methods. Using audiometry and genetic analysis, we searched for WFS1 mutations in three unrelated Japanese patients with LFSNHL and a familial history of autosomal dominant hearing loss. Results. One patient carried a heterozygous G2700A mutation at codon 844 in exon 8, resulting in substitution of a threonine for an alanine (A844T). Genetic analysis of the available members of the patient's family showed that the A844T mutation segregated with LFSNHL, but was not detected in any of 140 control chromosomes. It thus appears likely that the A844T mutation is causative for hearing loss in this group. Speech audiometry, self-recording audiometry and auditory brainstem responses showed the patient to have cochlear deafness without retrocochlear dysfunction. No mutation was found in the other two patients.     

A mutation in Wolfram syndrome type 1 gene in a Japanese family with autosomal dominant low-frequency sensorineural hearing loss

CONCLUSION: Our findings suggest that Wolfram syndrome type 1 gene (WFS1) mutation is an important cause of autosomal dominant low-frequency sensorineural hearing loss (LFSNHL) in Japan. OBJECTIVE: DFNA6/14 is caused by a heterozygous mutation of WFS1 and is a common cause of autosomal dominant LFSNHL among populations in both Europe and the US. The purpose of this study was to investigate WFS1 mutations among Japanese patients whose phenotypes were consistent with those of DFNA6/14. MATERIAL AND METHODS: Using audiometry and genetic analysis, we searched for WFS1 mutations in three unrelated Japanese patients with LFSNHL and a familial history of autosomal dominant hearing loss. RESULTS: One patient carried a heterozygous G2700A mutation at codon 844 in exon 8, resulting in substitution of a threonine for an alanine (A844T). Genetic analysis of the available members of the patient's family showed that the A844T mutation segregated with LFSNHL, but was not detected in any of 140 control chromosomes. It thus appears likely that the A844T mutation is causative for hearing loss in this group. Speech audiometry, self-recording audiometry and auditory brainstem responses showed the patient to have cochlear deafness without retrocochlear dysfunction. No mutation was found in the other two patients.     

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.