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.

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.

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.

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.

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.

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 .

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.

Breeding,Genotyping and Hearing Examination of the GJB2 Conditional Knock Out Mice / 听力学及言语疾病杂志

Objective To explore the methods of breeding ,reproduction and genotype of GJB2 knock -out (cCx26KO) mice and further study the critical role of GJB2 mutation in the onset of nonsyndromic hearing loss (NSHL) .Methods Two pairs of transgenic mice (Cx26loxp/loxp and Pax2 -Cre/+ ) were inbreeded to produce Cx26loxp/-_Pax2-Cre/+ ones ,female of which were used to mate with the male Cx26loxp/loxp ones to finally get the Cx26loxp/loxp_Pax2 -Cre/+ mice(cCx26KO) .The genotype was done by PCR and Agarose gel electro-phoresis using genome DNA extracted from the mice tails .The c-ABR was used to detect the hearing ability of the cCx26KO mice .Results Both breeding and reproduction of cCx26KO mice were successful .It was fruitful to obtain four genotype mice(Cx26loxp/loxp_ Pax2-Cre / + ,Cx26loxp / -_Pax2-Cre / + ,Cx26loxp/loxp ,Cx26loxp /-) by the breeding Cx26loxp / -_Pax2Cre / + and Cx26loxp/loxp mice .The results of breeding were met with the Mendel's law .The c-ABR revealed elevated response threshold around 95 dB SPL in cCx26KO mouse compared to the wild type ones ,which further validated the accuracy of the PCR method .Conclusion The PCR method is cor-rectly identified sub pups genotype and the female Cx26loxp/-_Pax2-Cre/+ mice mating with the male Cx26loxp/loxp ones is an effective way to obtain the cCx 26KO mice .

Progress in GJB2 gene and its diagnostic screening technique / 国际儿科学杂志

Deafness gene GJB2 is located in 13q11-q12,which codes for the protein connexin 26(CX26). Up to 50% of autosomal recessive nonsyndromic hearing loss are accounted for by mutations in the GJB2 gene. However, in different ethnic groups, the mutational sites of GJB2 gene are also different. For examples, 35delG is the most common mutation in Europe and USA. In Ashkenazi Jews, 167delT is most common. While among the Asians,235delC is makes up a large proportion of the GJB2 gene mutation. Because of the special status of GJB2 gene in hereditary hearing loss, its diagnostic screening technique is especially important. On the basis of newborn hearing screening, it is suggested that we should be to blend into the deaf disease gene screening at the molecular level, because they play an important role in early detection and intervention on congenital hearing loss.

A novel missense mutation p. L76P in the GJB2 gene causing nonsyndromic recessive deafness in a Brazilian family

Mutations in the GJB2 gene, encoding connexin 26 (Cx26), are a major cause of nonsyndromic recessive hearing loss in many countries. We report here on a novel point mutation in GJB2, p.L76P (c.227C>T), in compound heterozygosity with a c.35delG mutation, in two Brazilian sibs, one presenting mild and the other profound nonsyndromic neurosensorial hearing impairment. Their father, who carried a wild-type allele and a p.L76P mutation, had normal hearing. The mutation leads to the substitution of leucine (L) by proline (P) at residue 76, an evolutionarily conserved position in Cx26 as well as in other connexins. This mutation is predicted to affect the first extracellular domain (EC1) or the second transmembrane domain (TM2). EC1 is important for connexon-connexon interaction and for the control of channel voltage gating. The segregation of the c.227C>T (p.L76P) mutation together with c.35delG in this family indicates a recessive mode of inheritance. The association between the p.L76P mutation and hearing impairment is further supported by its absence in a normal hearing control group of 100 individuals, 50 European-Brazilians and 50 African-Brazilians.