Lack of methylation changes in GJB2 and RB1 non-coding regions of cochlear implant patients with sensorineural hearing loss

Objective@#Recent advances in epigenetic studies continue to reveal novel mechanisms of gene regulation and control, however little is known on the role of epigenetics in sensorineural hearing loss (SNHL) in humans. We aimed to investigate the methylation patterns of two regions, one in RB1 and another in GJB2 in Filipino patients with SNHL compared to hearing control individuals. @*Methods@#We investigated an RB1 promoter region that was previously identified as differentially methylated in children with SNHL and lead exposure. Additionally, we investigated a sequence in an enhancer-like region within GJB2 that contains four CpGs in close proximity. Bisulfite conversion was performed on salivary DNA samples from 15 children with SNHL and 45 unrelated ethnically-matched individuals. We then performed methylation-specific real-time PCR analysis (qMSP) using TaqMan® probes to determine percentage methylation of the two regions. @*Results@#Using qMSP, both our cases and controls had zero methylation at the targeted GJB2 and RB1 regions. @*Conclusion@#Our study showed no changes in methylation at the selected CpG regions in RB1 and GJB2 in the two comparison groups with or without SNHL. This may be due to a lack of environmental exposures to these target regions. Other epigenetic marks may be present around these regions as well as those of other HL-associated genes.

A case of classical Vohwinkel syndrome caused by the mutation p.N54H in the GJB2 gene / 中华皮肤科杂志

Objective:To detect gene mutations in 1 patient with Vohwinkel syndrome who presented with palmoplantar keratoderma, pseudo-ainhum and deafness.Methods:Clinical data were collected from the proband, and a genetic test was performed to identify mutation sites.Results:Clinical manifestations of the proband were consistent with classical Vohwinkel syndrome. The genetic test revealed a heterozygous mutation c.160A>C (p.N54H) in the GJB2 gene, which was not detected in her parents or healthy controls.Conclusion:The heterozygous mutation c.160A>C (p.N54H) in the GJB2 gene was first identified in a patient with classical Vohwinkel syndrome, and there were overlaps in mutation sites between classical Vohwinkel syndrome and palmoplantar keratoderma with deafness.

Congenital hearing loss: a literature review of the genetic etiology in a Mexican population / Pérdida auditiva congénita: revisión de la etiología genética en la población mexicana

Abstract Hearing loss is the most frequent sensory disorder, with an incidence of 1:1500 live newborns. In more than 50% of patients, it is associated with a genetic cause, while in up to 30% of cases, it is related to syndromic entities. We performed a literature review of studies on congenital hearing loss of genetic origin in the Mexican population. We identified eight reports that showed that the pathogenic variants most frequently associated with hearing loss are related to the GJB2 gene, although in a low percentage (3%). Other mutations were identified in the GJB6, SLC26A4, or CHD23 genes. On this basis, a possible diagnostic strategy in Mexican patients with hearing loss is to consider an initial screening of these three genes. If these genes were negative for pathogenic variants, the following steps would be to consider second-generation sequencing analysis focused on panels of genes associated with hearing loss, isolated or syndromic, and if necessary, to perform exome or whole-genome analysis. Establishing an etiologic cause is critical in clinically evaluating patients with congenital hearing loss and their families. It can help determine rehabilitation strategies, such as hearing aids or cochlear implants and provide information on disease progression and genetic counseling in this population.

Resumen La pérdida auditiva es la alteración sensorial más frecuente, con una incidencia de 1:1500 recién nacidos vivos. En más del 50% de los pacientes se asocia con una causa genética, mientras que en más del 30% de los casos se asocia con entidades sindrómicas. Se llevó a cabo una revisión de la literatura de las investigaciones sobre la pérdida auditiva congénita de origen genético en la población mexicana. Se identificaron ocho reportes en los que se demostró que las variantes patogénicas más frecuentemente asociadas con pérdida auditiva se encuentran en el gen GJB2, aunque en un porcentaje bajo (3%). Se identificaron otras mutaciones en los genes GJB6, SLC26A4 o CHD23. Con base en esta información, una posible estrategia diagnóstica en pacientes mexicanos con pérdida auditiva es considerar un primer paso en el tamiz diagnóstico con los tres genes mencionados. Si estos genes fueran negativos para variantes patogénicas, el siguiente paso sería considerar el análisis por secuenciación de segunda generación enfocado en paneles de genes asociados con pérdida auditiva, tanto aislada como sindrómica, y en caso necesario, realizar el análisis del exoma o del genoma completo. Establecer una causa etiológica es un componente crítico en la evaluación clínica de los pacientes con pérdida auditiva congénita, ya que puede ayudar a determinar las estrategias de manejo y rehabilitación, como el uso de auxiliares auditivos o implantes cocleares, proporcionar información sobre la progresión de la enfermedad y dar asesoramiento genético en esta población.

Molecular study of hearing loss in Minas Gerais, Brazil / Estudo molecular da perda auditiva em Minas Gerais, Brasil

Abstract Introduction: Deafness is the most frequent sensory deficit in humans. Incidence is estimated at 4:1000 births in Brazil. Specific programs for clinical care of patients with hearing loss are still scarce in Brazil and the issue is an important public health problem. Objective: To determine the frequency of 35delG and D13S1830 mutations in GJB2 and GJB6 genes respectively in patients with non-syndromic sensorineural hearing loss from Minas Gerais, Brazil. Methods: This research involved 53 individuals, who were assessed by a questionnaire for predicting the possibility of non-syndromic deafness and for data collecting. Samples were tested for the presence of the 35delG mutation in GJB2 gene and D13S1830 in GJB6 gene by polymerase chain reaction and restriction enzyme digestion. Results: Epidemiological research has shown that the majority of the subjects are unaware of the etiology and the pathogenesis of hearing loss. In 9 patients (16.98%), 35delG mutation was found in heterozygosis and the allele frequency was estimate to be around 8.5%. Although 9.61% of the patients reported having some degree of consanguinity between the parents and 12.08% reported other cases of deafness in their families, this mutation was not found in homozygosis. The D13S1830 mutation was not found in this study. Conclusion: This research describes for the first time the frequency of the 35delG and D13S1830 mutation in hearing-impaired individuals from Minas Gerais, Brazil, and the collected data reinforce the need for further studies in this population due to heterogeneity of hearing loss.

Resumo Introdução: A surdez é o déficit sensorial mais frequente em humanos. Estima-se que a incidência seja de 4:1.000 nascimentos no Brasil. Programas específicos para atendimento clínico de pacientes com perda auditiva são escassos no Brasil e a questão é um importante problema de saúde pública. Objetivo: Determinar a frequência das mutações 35delG no gene GJB2 e D13S1830 no GJB6 em pacientes deficientes auditivos de origem neurossensorial e não sindrômica de Minas Gerais, Brasil. Método: A pesquisa envolveu 53 indivíduos selecionados por meio de questionário o qual avaliou a possibilidade de surdez não sindrômica entre outros dados. As amostras foram testadas quanto à presença da mutação 35delG no gene GJB2 e D13S1830 no gene GJB6 por reação em cadeia da polimerase e digestão com enzima de restrição. Resultados: A pesquisa epidemiológica mostrou que a maioria dos indivíduos desconhece a etiologia da perda auditiva. Em 9 pacientes (16,98%), a mutação 35delG foi encontrada em heterozigose e a frequência alélica foi estimada em 8,5%. Embora 9,61% das pessoas tenham relatado algum grau de consanguinidade entre os pais e 12,08% relatassem outros casos de surdez em suas famílias, essa mutação não foi encontrada em homozigose. A mutação D13S1830 não foi encontrada neste estudo. Conclusão: Este trabalho descreve pela primeira vez a frequência da mutação 35delG e D13S1830 em deficientes auditivos de Minas Gerais, Brasil, e os dados coletados reforçam a necessidade de mais estudos nessa população devido à heterogeneidade da perda auditiva.

Analysis of genotypes and hearing phenotypes of mutation infants with deafness / 临床耳鼻咽喉头颈外科杂志

The aim of this study is to explore the genotype and hearing phenotype of deaf infants with mutation of gene. Subjects were 121 infants with gene mutations who were treated in the Children's Hearing Diagnosis Center of Beijing Tongren hospital. All subjects were accepted to undertake the universal newborns hearing screening（UNHS） and series of objective audiometry, including auditory brainstem response, distortion product otoacoustic emission, auditory steady-state response and other audiological tests. All subjects were screened for nine pathogenic variants in four genes or all exons of the gene, and then were diagnosed as infants with gene mutations. Initially, analyzing their genotypes and hearing phenotypes generally. Then, the subjects were divided into two groups according to the genotypes: T/T group（truncated/truncated mutations, 89 cases） and T/NT group（truncated/non-truncated mutations, 32 cases）. Chi-square test was used to analyze the results of UNHS, hearing degree, audiogram patterns and symmetry/asymmetry of binaural hearing phenotype. Eventually, analyzing the results of UNHS. The most common truncated mutation was c.235delC（64.88%, 157/242） and the most common non-truncated mutation was c.109G>A（11.16%, 27/242）. The homozygous mutation of c.235delC/c.235delC was the dominant in T/T group（38.84%, 47/121）, and the compound heterozygous mutation of c.235delC/c.109G>A was the dominant in T/NT group（18.18%, 22/121）. 81.82%（99/121） of subjects failed in UNHS, including 74.38%（90/121） with bilateral reference, 7.44%（9/121） with a single pass. The refer rate of UNHS of group T/T and T/NT were 86.52%（77/89） and 68.75%, respectively. There was a statistically significant difference between the two groups（0.05）. In this study, c.235delC/c.235delC homozygous mutation was dominant in T/T group and c.235delC/c.109G>A heterozygous mutation was dominant in T/NT Group. The hearing phenotypes in T/T group were mostly bilateral asymmetric severe hearing loss, and those in T/NT Group were bilateral symmetric mild to moderate hearing loss, special attention should be paid to the audiological characteristics of different genotypes.

Analysis of genotypes and hearing phenotypes of mutation infants with deafness / 临床耳鼻咽喉头颈外科杂志

Objective@#The aim of this study is to explore the genotype and hearing phenotype of deaf infants with mutation of GJB2 gene.@*Method@#Subjects were 121 infants with GJB2 gene mutations who were treated in the Children's Hearing Diagnosis Center of Beijing Tongren hospital. All subjects were accepted to undertake the universal newborns hearing screening（UNHS） and series of objective audiometry, including auditory brainstem response, distortion product otoacoustic emission, auditory steady-state response and other audiological tests. All subjects were screened for nine pathogenic variants in four genes or all exons of the GJB2 gene, and then were diagnosed as infants with GJB2 gene mutations. Initially, analyzing their genotypes and hearing phenotypes generally. Then, the subjects were divided into two groups according to the genotypes: T/T group（truncated/truncated mutations, 89 cases） and T/NT group（truncated/non-truncated mutations, 32 cases）. Chi-square test was used to analyze the results of UNHS, hearing degree, audiogram patterns and symmetry/asymmetry of binaural hearing phenotype. Eventually, analyzing the results of UNHS. @*Result@#The most common truncated mutation was c.235delC（64.88%, 157/242） and the most common non-truncated mutation was c.109G>A（11.16%, 27/242）. The homozygous mutation of c.235delC/c.235delC was the dominant in T/T group（38.84%, 47/121）, and the compound heterozygous mutation of c.235delC/c.109G>A was the dominant in T/NT group（18.18%, 22/121）. 81.82%（99/121） of subjects failed in UNHS, including 74.38%（90/121） with bilateral reference, 7.44%（9/121） with a single pass. The refer rate of UNHS of group T/T and T/NT were 86.52%（77/89） and 68.75%, respectively. There was a statistically significant difference between the two groups（P<0.05）. 85.95%（104/121） of subjects were diagnosed as hearing loss and 14.05%（17/121） of subjects were diagnosed as normal hearing. The degree of hearing loss: profound, severe, moderate and mild were 31.40%（38/121）, 19.01%（23/121）, 24.79%（30/121） and 10.74%（13/121）, respectively. There was no subjects with normal hearing in T/T group and individuals with severe and profound hearing loss accounted for the highest proportion（65.17%, 58/89）, while in T/NT group, normal hearing accounted for 53.13%（17/32） and mild and moderate hearing loss accounted for the highest proportion（37.5%, 12/32）. There was statistically significant difference between the two groups（P<0.05）. Of 104 patients（208 ears） with hearing loss, the audiogram patterns: flat, descending, ascending, residual, Valley and other types were 49.03%（102/208）, 12.02%（25/208）, 8.65%（18/208）, 7.69%（16/204）, 3.36%（7/204） and 19.23%（40/204）, respectively. The two most common types in T/T group were flat（47.19%, 84/178） and other types（20.22%, 36/178）, while in T/NT group were flat（60.00%, 18/30） and ascending（20.00%, 6/30）. There was statistically significant difference between the two groups（P<0.05）. There were 50 cases（48.07%） with symmetrical hearing phenotype and 54 cases（51.93%） with asymmetrical hearing phenotype. Asymmetry was predominant in T/T group（53.93%, 48/89）, and symmetry was predominant in T/NT group（60.00%, 9/15）. There was no statistically significant difference between the two groups（P>0.05）. @*Conclusion@#In this study, c.235delC/c.235delC homozygous mutation was dominant in T/T group and c.235delC/c.109G>A heterozygous mutation was dominant in T/NT Group. The hearing phenotypes in T/T group were mostly bilateral asymmetric severe hearing loss, and those in T/NT Group were bilateral symmetric mild to moderate hearing loss, special attention should be paid to the audiological characteristics of different genotypes.

Genetics of Hearing Loss in North Iran Population: An Update of Spectrum and Frequency of GJB2 Mutations

Diagnosis of pre-lingual hearing loss (HL) is difficult owing to the high number of genes responsible. The most frequent cause of HL is DFNB1 due to mutations in the GJB2 gene. It represents up to 40% of HL cases in some populations. In Iran, it has previously been shown that DFNB1 accounts for 16-18% of cases but varies among different ethnic groups. Here, we reviewed results from our three previous publications and data from other published mutation reports to provide a comprehensive collection of data for GJB2 mutations and HL in northern Iran. In total, 903 unrelated families from six different provinces, viz., Gilan, Mazandaran, Golestan, Ghazvin, Semnan, and Tehran, were included and analyzed for the type and prevalence of GJB2 mutations. A total of 23 different genetic variants were detected from which 18 GJB2 mutations were identified. GJB2 mutations were 20.7% in the studied northern provinces, which was significantly higher than that reported in southern populations of Iran. Moreover, a gradient in the frequency of GJB2 mutations from north to south Iran was observed. c.35delG was the most common mutation, accounting for 58.4% of the cases studied. This study suggests that c.35delG mutation in GJB2 is the most important cause of HL in northern Iran.

Nevo poroqueratósico del ostium y el ducto dérmico ecrinos: reporte de caso / Porokeratotic eccrine ostial and dermal duct nevus: case report

El Nevo Poroqueratósico del Ostium y el Ducto Dérmico Ecrinos (NPODDE), es un raro hamartoma benigno de los conductos de las glándulas sudoríparas ecrinas, puede presentarse desde el nacimiento o también en edades posteriores. Su etiología plantea una alteración en la queratinización debido a una mutación somática en el gen GJB2 que codifica para una proteína de unión gap. Esta mutación también está relacionada con el síndrome KID por lo cual la asesoría genética es crucial en estos pacientes. Clínicamente puede presentarse como hoyuelos hiperqueratósicos en palmas y plantas que normalmente son asintomáticos. El diagnostico se confirma con la histopato-logía que muestra una laminilla cornoide sobre el conducto ecrino subyacente. La entidad es benigna y de difícil tratamiento siendo refractaria a varias modalidades terapéuticas. Se presenta un caso de un paciente adulto masculino con lesiones típicas en palmas y plantas, a quien con la biopsia de piel se le confirmó el diagnóstico de NPODDE. Dado la baja frecuencia de esta condición el objetivo de este artículo radica en actualizar los aspectos más relevantes de esta entidad.

Porokeratotic Eccrine Ostial and Dermal Duct Nevus (PEODDN) is a rare benign hamartoma of eccrine sweat gland ducts, it can present from birth or also at later ages. Its etiology implies an alteration in keratinization due to a somatic mutation in GJB2 gene, that codes for a gap junction protein. This mutation is also associated with KID syndrome so genetic counseling for parents is crucial. Clinically it can present as keratotic pits in palms and soles that are usually asymp-tomatic. The diagnosis is confirmed by histopathology that shows a cornoid lamellae on the underlying eccrine duct. The entity is benign and the treatment is difficult, being refractory to seve-ral therapeutic modalities. We present a case of a male adult patient with typical lesions on palms and soles, who was diagnosed with PEODDN by skin biopsy. Given the low frequency of this con-dition, the objective of this article is to update the most relevant aspects of this entity.

СОНСГОЛЫН ХҮНД ХЭЛБЭРИЙН БУУРАЛТТАЙ ХҮНД CONNEXIN 26 ГЕНИЙН МУТАЦИЙГ ТОДОРХОЙЛСОН ТӨСӨЛТ АЖЛЫН ЗАРИМ ҮР ДҮН / Шинэ санаа Шинэ нээлт

@#BACKGROUND. Sensorineural hearing impairment (SNHI) is the most common inherited sensory defect, affecting about 3 per 1000 children. More than 50% of these patients have a genetic cause (i.e. hereditary hearing impairment; HHI). Mutations in certain genes were noted to be extraordinarily popular in the deaf patients across different populations, making molecular screening feasible for these common deafness genes. One of the most important characteristics that we have learned concerning hereditary hearing loss is that common deafness genes and their mutations are usually different according to the ethnic background. As demonstrated in our previous studies performed in Taiwanese patients, the mutation spectrums of common deafness genes, such as the GJB2 gene and the SLC26A4 gene, are different from those in the Caucasian or even other Asian populations. These findings further underscore the indispensability of the collection of local data in terms of genetic counseling. In the collaborative project, we have successfully established a cohort of >100 hearingimpaired families, and clarified the genetic epidemiology of deafness in the Mongolian population. We identified several special deafness mutations such as GJB2 c.23+1G>A, c.559_604dup, and SLC26A4 c.919-2A>G, and our results revealed that Mongolian patients demonstrate a unique genetic profile in deafness as compared to other East Asian populations (paper in preparation). Meanwhile, by organizing a seminar at National Taiwan University Hospital in March 2017, we have transferred crucial concepts and techniques regarding how to perform genetic testing for deafness to the Mongolian colleagues. In the future, we plan to strengthen the mutual collaboration by expanding the clinical cohort and upgrading the genetic examination platform using the NGS techniques.

Evaluation of electrocardiographic parameters in patients with hearing loss genotyped for the connexin 26 gene (GJB2) mutations / Avaliação dos parâmetros eletrocardiográficos em pacientes com perda auditiva genotipada para mutações do gene conexina 26 (GJB2)

Abstract Introduction: Several studies have associated congenital sensorineural hearing loss in children with prolongation of the cardiac parameter QTc. The cause of this association is unknown. At the same time, mutations in GJB2, which encodes connexin 26, are the most common cause of congenital hearing impairment. Objective: To compare electrocardiographic parameters (PR interval, QRS complex, and QTc interval) in patients with hearing loss who were tested for mutations in GJB2 and GJB6 to investigate whether these mutations affect electrical activity of the heart. Methods: 346 patients (176 males, 170 females) with sensorineural hearing loss of 30 dB HL or more, aged 21.8 ± 19.9 years (including 147 children <14 years), underwent both genetic study for GJB2 and GJB6 mutations and electrocardiography. Results: Mutations in GJB2, including homozygotes and heterozygotes, were found in 112 (32%) patients. There were no significant differences in ECG parameters between groups of patients with and without mutations in GJB2. No differences were observed either in men (mean PR with mutation: 155 ± 16.6 vs. 153.6 ± 30.1 without; QRS: 99.9 ± 9.9 vs. 101.1 ± 15.4; QTc: 414.9 ± 29.9 vs. 412.4 ± 25.7) or women (mean PR with: 148.7 ± 21 vs. 143.8 ± 22.8 without; QRS: 94.8 ± 7.6 vs. 92.9 ± 9.6; QTc: 416.8 ± 20.6 vs. 424.9 ± 22.8). In similar fashion, we did we find any significant differences between groups of children with and without GJB2 mutations (mean PR with: 126.3 ± 19.6 vs. 127 ± 19.7 without; QRS: 80.7 ± 9.5 vs. 79.4 ± 11.6; QTc: 419.7 ± 23.5 vs. 419.8 ± 24.8). Conclusion: No association was found between the presence of GJB2 mutations encoding connexin 26 in patients with hearing loss and their ECG parameters (PR, QRS, QTc).

Resumo Introdução: Vários estudos têm associado a perda auditiva neurossensorial congênita em crianças ao prolongamento do parâmetro cardíaco QTc. A causa dessa associação é desconhecida. Ao mesmo tempo, as mutações no GJB2, que codifica a conexina 26, são a causa mais comum de deficiência auditiva congênita. Objetivo: Comparar parâmetros eletrocardiográficos (intervalo PR, complexos QRS e intervalo QTc) em pacientes com perda auditiva que foram testados para mutações no GJB2 e GJB6 para investigar se essas mutações afetam a atividade elétrica do coração. Método: Foram submetidos a estudo genético para mutações de GJB2 e GJB6 e eletrocardiograma 346 pacientes (176 homens, 170 mulheres) com perda auditiva neurossensorial de 30 dB ou mais, com média de 21,8 ± 19,9 anos (incluindo 147 crianças <14 anos). Resultados: Mutações no GJB2, inclusive homozigóticos e heterozigóticos, foram encontradas em 112 (32%) pacientes. Não houve diferenças significativas nos parâmetros de ECG entre grupos de pacientes com e sem mutações no GJB2. Não foram observadas diferenças em homens (PR médio com mutação: 155 ± 16,6 vs. 153,6 ± 30,1 sem mutação; QRS: 99,9 ± 9,9 vs. 101,1 ± 15,4; QTc: 414,9 ± 29,9 vs. 412,4 ± 25,7) nem em mulheres (PR médio com: 148,7 ± 21 vs. 143,8 ± 22,8, sem; QRS: 94,8 ± 7,6 vs. 92,9 ± 9,6; QTc: 416,8 ± 20,6 vs. 424,9 ± 22,8). Da mesma forma, encontramos diferenças significativas entre os grupos de crianças com e sem mutações de GJB2 (PR médio com: 126,3 ± 19,6 vs. 127 ± 19,7, sem; QRS: 80,7 ± 9,5 vs. 79,4 ± 11,6; QTc: 419,7 ± 23,5 vs. 419,8 ± 24,8). Conclusão: Não foi encontrada associação entre a presença de mutações de GJB2 que codificam conexina 26 em pacientes com perda auditiva e seus parâmetros de ECG (PR, QRS, QTc).

Keratitis, ichthyosis, and deafness syndrome: a case report / 中华皮肤科杂志

A 10 year-old female child developed erythema on the scalp,perioral area,neck,trunk,buttocks,palms and soles within 1 month after birth.Her skin was dry and rough,and the hairs were fine,soft,sparse and easily broken.As age advanced,typical hyperkeratosis and thickening of the skin occurred on an erythematous base.At the age of 5 years,the child developed photophobia and vision impairment.When the child was 8 years old,progressive hearing loss was observed.Physical examination revealed that the height and weight were 109 centimeters and 19 kilograms respectively.Skin examination showed fine,soft,sparse and easily-broken hair,large areas of brown plaques with crusts on the scalp,perioral area,neck,trunk and buttocks,and fissured,purulent and foul-smelling verrucous hyperplasia over these plaques.Brown to black hyperkeratotic plaques were scattered over the extremities,and diffuse hyperkeratosis occurred on the palms and soles.Both fingernails and toenails became thickened,cloudy and white with distal separation and deformation of the nail plate.As ophthalmic examination showed,the patient had photophobia,bilateral bulbar conjunctival hyperemia,corneal opacity and corneal vascular proliferation,and the visual acuity was 0.5 in the left eye and 0.2 in the right eye.Otolaryngological examination revealed moderate binaural sensorineural deafness.Stomatological examination showed enamel hypoplasia and diastema widening.Genetic testing showed a heterozygous mutation (c.C50T) in exon 2 of the gap junction protein beta 2 (GJB2) gene.Based on these clinical manifestations and examinations,the patient was diagnosed with keratitis,ichthyosis,and deafness (KID) syndrome.Skin lesions of the patient were significantly improved after the treatment with oral acitretin.

Genetic analysis and prenatal diagnosis for patients with non-syndromic hearing impairment / 天津医药

Objective To explore the genetic pathogen of patients with non-syndromic hearing impairment and to provide prenatal diagnosis for the families of hereditary deafness. Methods Mutation screening of GJB2, SLC26A4, GJB3 and mitochondrial 12 S rRNA genes was performed in 208 patients with non-syndromic hearing impairment by gene chip. Then direct sequencing was used in 41 patients who were found one mutation of GJB2 or SLC26A4 gene. And prenatal diagnosis was carried out in two families by direct sequencing. Results Eighty-six patients (41.35％) were found at least one mutation by gene chip. Among them, 40 patients were found to carry two mutations and 46 patients were found to carry one mutation. The most frequent mutation was 235delC, which was found in 46 patients. And 12 cases were found the second mutation through direct sequencing. A total of 52 (25.00％) patients were detected two mutations. Prenatal diagnosis showed that one fetus carried compound mutations of 299-300delAT and 235delC, and another one carried heterozygous mutation of IVS7-2A>G. Conclusion Patients with non-syndromic hearing impairment can be accurately diagnosed by gene chip and Sanger sequencing. The prenatal diagnosis is primary means for high-risk fetuses.

Analysis of deafness-associated mutant genes and pedigrees in neonates / 预防医学

Objective To carry out mutation analysis of deafness-associated genes for deaf newborns and their parents, and to estimate the recurrence risk for their parents to have deaf descendants.Methods Suspected cases of inherited deafness were identified by neonatal hearing screening and questionnaires. Genomic DNAs of suspected cases and their parents were extracted from their peripheral blood samples . Common deafness-associated genes(i.e. GJB2,SLC26A4 and 12S rRNA genes)were amplified by polymerase chain reaction(PCR),and those PCR products were sequenced for the mutation analysis.Results From 2013 to 2016, 193 cases of deafness were found in neonatal hearing screening,29 cases of suspected as hereditary deafness were screened,and 17 out of 29 cases were found to have mutations in deafness-associated genes(detection rate:58.62%). GJB2 homozygous mutations were identified in two cases and their parents,and the recurrence risk to have deaf descendants was 100%. Four cases of suspected hereditary deafness had GJB2 homozygous mutations,and their parents were both GJB2 mutation carriers. There was one case with SLC26A4 homozygous mutations,and their parents were both SLC26A4 mutation carrier. Two cases were detected to have GJB2 V371 homozygous mutations,and their parents were both GJB2 V371 mutation carriers. For those seven parents carrying deafness-associated mutations above,the recurrence risk of deafness for their descendants was 25%.Conclusion In addition to hearing screening,the genetic diagnosis of deafness-associated genes is helpful to clarify the cause of suspected neonatal hereditary deafness,and can provide objective reproductive counseling and guidance for those deaf parents or parents with deaf children.

МОНГОЛ ХҮНИЙ ТӨРӨЛХИЙН БОЛОН ОЛДМОЛ ХЭЛБЭРИЙН ДҮЛИЙН ҮЕИЙН CONNEXIN 26 ГЕНИЙН МУТАЦИЙГ ТОДОРХОЙЛСОН СУДАЛГААНЫ АЖЛЫН ЗАРИМ ҮР ДҮН / Шинэ санаа Шинэ нээлт

@#BACKGROUND. Sensorineural hearing impairment (SNHI) is the most common inherited sensory defect, affecting about 3 per 1000 children. More than 50% of these patients have a genetic cause (i.e. hereditary hearing impairment; HHI). Mutations in certain genes were noted to be extraordinarily popular in the deaf patients across different populations, making molecular screening feasible for these common deafness genes. One of the most important characteristics that we have learned concerning hereditary hearing loss is that common deafness genes and their mutations are usually different according to the ethnic background. As demonstrated in our previous studies performed in Taiwanese patients, the mutation spectrums of common deafness genes, such as the GJB2 gene and the SLC26A4 gene, are different from those in the Caucasian or even other Asian populations. These findings further underscore the indispensability of the collection of local data in terms of genetic counseling. In the collaborative project, we have successfully established a cohort of >100 hearing-impaired families, and clarified the genetic epidemiology of deafness in the Mongolian population. We identified several special deafness mutations such as GJB2 c.23+1G>A, c.559_604dup, and SLC26A4 c.919-2A>G, and our results revealed that Mongolian patients demonstrate a unique genetic profile in deafness as compared to other East Asian populations (paper in preparation). Meanwhile, by organizing a seminar at National Taiwan University Hospital in March 2017, we have transferred crucial concepts and techniques regarding how to perform genetic testing for deafness to the Mongolian colleagues. In the future, we plan to strengthen the mutual collaboration by expanding the clinical cohort and upgrading the genetic examination platform using the NGS techniques.

The analysis of common mutation in deafness-associated gene in 111 neonates who failed to pass newborn hearing screening / 临床儿科杂志

Objective To explore the genetic mutation in neonates who failed to pass hearing screening.Methods A total of 111 cases of neonates who failed to pass hearing screening and were conifrmed sensorineural deafness by auditory brainstem evoked potential (ABR) were randomly selected. The heel blood was collected and DNA was extracted.GJB2, SLC26A4, and 11 mutation hotspots in mitochondria gene12SrRNA were tested. The relationship between degree of hearing loss and gene mutation was analyzed.Results In 111 neonates, mutation in deafness gene were found in 24 cases (21.6%) . Among them 14 cases (12.6%) hadGJB2 gene mutation including 5 cases of 235delC single heterozygous mutation, 5 cases of 235delC, and 1 case each of 299_300delAT compound heterozygous mutation, 235delC homozygous mutation, 299_300delAT single heterozygous mutation, 176_191del16 and 235delC compound heterozygous mutation, and 299_300delAT and 508_511dupAACG compound heterozygous mutation respectively. Ten cases (9.0%) hadSLC26A4 gene mutation including 2 cases of IVS7-2A>G single heterozygous mutation, 3 cases of 1226G>A single heterozygous mutation, 2 cases of 2168A>G single heterozygous mutation, and 3 cases of IVS7-2A>G and 2168A>G compound heterozygous mutation. Mitochondrial gene mutations were not detected. Conclusions Deafness gene mutation is detected in more than 1/5 neonates who failed to pass newborn hearing screening. GJB2 gene mutation is the most commons. The implementation of hotspots deafness gene detection can improve the diagnostic rate of deafness.

Investigation of the GJB6 Deletion Mutations Del (GJB6-D13s1830) and Del (GJB6-D13s1854) in Iranian Patients with Autosomal-Recessive Non-Syndromic Hearing Loss (ARNSHL)

Hearing loss (HL) is the most common inherited sensory disorder affecting about 1 in 1000 births. The first locus for nonsyndromic autosomal recessive HL is on chromosome 13q11-22. The two genes, GJB2 and GJB6, are closely located on chromosome and are known to be co-expressed in the embryonic cochlea. Deletion mutations involving GJB6 were associated with autosomal-recessive nonsyndromic hearing loss (ARNSHL) and in combination with a GJB2 mutation with digenic ARNSHL. The objective of this study was to screen for the del (GJB6-D13S1830) and del (GJB6-D13s1854) mutations in GJB6 gene in patients with ARNSHL from Iran, using multiplex PCR and direct sequencing methods. Agarose gel electrophoresis and DNA sequencing of amplified fragment of the PCR reaction showed none of the patients was found to carry deletion in GJB6 gene which indicates that these deletions are restricted to certain populations and indicating a founder effect regarding these deletions.

A case of keratitis-ichthyosis-deafness syndrome complicated by cutaneous squamous cell carcinoma：mutation analysis of the GJB2 gene and literature review / 中华皮肤科杂志

Objective To analyze mutations in the GJB2 gene in a Chinese patient with keratitis-ichthyosis-deafness (KID)syndrome complicated by cutaneous squamous cell carcinoma. Methods Clinical data were collected from a patient with KID syndrome complicated by cutaneous squamous cell carcinoma. Peripheral blood samples were obtained from the patient and her parents, and DNA was extracted from these blood samples. PCR was performed to amplify the exon 2 of the GJB2 gene followed by direct DNA sequencing. Results A mutation (c.148G > A)was identified at position 148 in exon 2 of the GJB2 gene, which caused a codon change from GAC to AAC and resulted in the substitution of aspartate by asparagine at position 50 in the connexin26 (Cx26)protein (p.Asp50Asn). Inaddition,anothermutation(c. 79G > A), which led to the substitution of valine by isoleucine at codon 27 in Cx26 (p.Val27Ile), was found at position 79 in exon 2 of the GJB2 gene. Neither of the two mutations was detected in the patient′s parents. Literature review revealed that 13 cases of KID syndrome complicated by cutaneous squamous cell carcinoma had been reported in abroad, and the mutation c.148G > A was detected in the GJB2 gene in all the 7 cases finally diagnosed by gene sequencing. Conclusion GJB2 gene mutations may be responsible for the clinical phenotype of KID syndrome in this Chinese patient, and the mutation c.148G > A may be related to the development of cutaneous squamous cell carcinoma.

A Mutation Analysis of GJB2 and SLC26A4 Gene in A Chinese Family wi th Non-Syndromi c Deafness / 听力学及言语疾病杂志

Objective To study the molecular pathogenesis of non -syndromic deafness in a Chinese family . Methods Clinical materials and DNA sample were obtained from the non -syndromic family with autosomal reces‐sive deafness .The exons and the flanking splicing sites of GJB2 and SLC26A4 were tested in all family members by PCR and direct sequencing .Results There were four deafness patients in the family ,and three of them had the same clinical phenotypes ,including prelingual profound sensorineural hearing loss and enlarged vestibular ,while the re‐mained one only presented to be prelingual profound sensorineural hearing loss without malformation of temporal bone .One type of GJB2 mutation and 3 different types of SLC26A4 mutations were identified in the family .The proband(Ⅲ -1) ,her sister(Ⅲ -2) ,her mother(Ⅱ -4) and her father(Ⅱ -3) carried different biallelic mutations which were SLC26A4 c .919 -2A > G/p .H723R ,p .Q413R/c .919 -2A > G ,p .Q413R/p .H723R and GJB2 c . 235delC/c .235delC ,respectively .Conclusion Different from most reported deafness families with the same molecu‐lar etiology in each one ,interestingly ,the pathogenies were different among all affected members in this family . They were caused by different biallelic mutations of SLC26A4 or GJB2 .

Mutational analysis of GJB2 gene in a Chinese family with nonsyndromic hearing loss / 重庆医学

Objective To analyze the clinical and genetic features of a Chinese family with nonsyndromic hearing loss ,and to find deafness‐causing mutations in the GJB2 gene .Methods After a detailed history and clinical examination ,genomic DNA was ex‐tracted from peripheral blood for the proband and their family members .Two exons of the GJB2 gene was amplified by polymerase chain reaction ,and the PCR products were subjected to automatic DNA sequencing .Finally ,the mutation analysis was performed by SeqMan software of DNASTAR to compare BLAST .Results All patients in this family had late‐onset and progressive hearing loss and ultimately involved all frequencies .Six SNP polymorphisms were found in this pedigree ,which were previously reported world‐wide ,c .79G > A(p .Val27Ile) ,c .341G > A(p .Glu114Gly) ,were also identified in this family .Four single nucleotide polymorphisms (SNPs) were firstly identified in the GJB2 3′‐UTR ,including g .4159T > C ,g .5142G/T ,g .5227G/A ,g .5352T /C .Two SNPs .Con‐clusion Mutation in exons of GJB2 gene was excluded as a pathogenic cause for nonsyndromic hearing loss in this family .

Study the Mutation Screening of GJB3,GJB2,mtDNA,SLC26A4 Gene in Hainan Population with Non-syndromic Hearing Impairment / 现代检验医学杂志

Objective To investigate the mutation screening of the GJB3,GJB2,mtDNA 1555 A>G and SLC26A4 gene in Hainan Pronive population with non-syndromic hearing impairment.Methods PCR were performed with one pair of primer in the coding sequence of GJB3,GJB2,mtDNA 1555 A>G and SLC26A4 gene.Bidirectional sequencing of PCR products was subsequently applied in 429 patients with hearing loss.Results 55 patients gene mutation of 429 patients were found. The point mutation in mtDNA was found in 5 patients (1.1 7%).1 5 5 5 A>G mutation of mtDNA was found in 4 patients. 1494 C>T mutation of mtDNA was found in one patients.GJB2 gene mutation was found in 25 patients (5.83%).235 del C mutation of GJB2 gene was found in 9 patients.235 del C/GJB2 299 del AT mutation was found in two patients.235 del C mutation was found in 10 patients.176 del 16 mutation was found in 4 patients.SLC26A4 mutation was found in 22 patients (5.13%).IVS7-2 A>G mutation of SLC26A4 was found in 4 patients.2168 A>G mutation of SLC26A4 was found in one patient.IVS7-2 A>G mutation was found in 12 patients.2168 A>G mutation was found in 5 patients.538 C>T mutation of GJB3 gene was found in 3 patient.IVS7-2A>G mutation and 2168 A>G muation of SLC26A4 gene was found in 4 of 22 EVA patients.Conclusion GJB2 gene and SLC26A4 gene have revealed responsible genes for Hainan deafness patients.