Application of PCR reverse dot blot in non-syndromic deafness gene detection / 临床耳鼻咽喉头颈外科杂志

To detect 20 common deafness gene mutations in non- syndromic deafness patients in China using PCR- RDB, and analyze and summarize the mutation data to explore the clinical value of this method. The PCR- RDB and Sanger sequencing were used to detect 20 common mutations of four deafness genes（, and ） in 500 patients with non- syndromic hearing loss . The Sanger sequencing was used to compare the sensitivity, specificity, positive predictive value, negative predictive value, and total coincidence rate of the deafness mutation detected by PCR- RDB. A total of 500 samples were detected. 147 wild- type samples, 81 homozygous mutant samples, 240 heterozygous mutant samples, 32 composite heterozygous mutant samples were detected using the PCR- RDB within the range of 20 gene mutations, which were identical to the Sanger sequencing results. GJB2 c.235delC and SLC26A4 c.919- 2 A>G are the most common hotspot mutations in this study, followed by mtDNA m. 1555 A>G. Compared with the Sanger sequencing method, the sensitivity, specificity, positive predictive value, negative predictive value, and total coincidence rate of the real- time fluorescence PCR melting curve method were 100%, and the Kappa value was one. PCR reverse dot-blot hybridization is a simple, rapid, sensitive and specific method for detecting 20 mutations of 4 common deafness genes in Chinese population, it is expected to be used in clinical detection of deafness genes in the future.

Application of PCR reverse dot blot in non-syndromic deafness gene detection / 临床耳鼻咽喉头颈外科杂志

Objective@#To detect 20 common deafness gene mutations in non- syndromic deafness patients in China using PCR- RDB, and analyze and summarize the mutation data to explore the clinical value of this method. @*Method@#The PCR- RDB and Sanger sequencing were used to detect 20 common mutations of four deafness genes（GJB2, GJB3, SLC26A4 and mtDNA） in 500 patients with non- syndromic hearing loss . The Sanger sequencing was used to compare the sensitivity, specificity, positive predictive value, negative predictive value, and total coincidence rate of the deafness mutation detected by PCR- RDB. @*Result@#A total of 500 samples were detected. 147 wild- type samples, 81 homozygous mutant samples, 240 heterozygous mutant samples, 32 composite heterozygous mutant samples were detected using the PCR- RDB within the range of 20 gene mutations, which were identical to the Sanger sequencing results. GJB2 c.235delC and SLC26A4 c.919- 2 A>G are the most common hotspot mutations in this study, followed by mtDNA m. 1555 A>G. Compared with the Sanger sequencing method, the sensitivity, specificity, positive predictive value, negative predictive value, and total coincidence rate of the real- time fluorescence PCR melting curve method were 100%, and the Kappa value was one. @*Conclusion@#PCR reverse dot-blot hybridization is a simple, rapid, sensitive and specific method for detecting 20 mutations of 4 common deafness genes in Chinese population, it is expected to be used in clinical detection of deafness genes in the future.

Genetic Screening of Deaf Mutation for 2545 Newborn / 中国康复理论与实践

Objective:To investigate the mutative rate and spectrum of common hereditary deafness genes in Chinese. Methods:Heel blood samples from 2545 infants born from January to October, 2018, were collected, and screened with microarray chip. Results:There were 119 children with mutation of deafness gene, including 60 cases (2.36%) with GJB2 mutation, male/female = 1∶1 (30/30); 48 (1.88%) with SLC26A4 mutation, male/female nearly 1∶1 (26/22); five (0.20%) with mutation of mitochondrial 12S rRNA gene; five (0.20%) with GJB3 mutation; one (0.04%) with heterozygosis in GJB2 235 and SLC26A4 IVS7-2 mutation. Other more, mutations of 1174A > T, 1229C > T and 15+5G>A of SLC26A4 were found in one child, respectively. Conclusion:The distribution of deafness gene loci has been investigated, which can be reference for prevention and control of hereditary deafness in Chinese.

Study on relationship between SLC26A4 gene IVS16+10C>T mutation and hereditary deafness / 中国中西医结合急救杂志

Objective To investigate the relationship between hereditary deafness and SLC26A4 gene IVS16+10C>T mutation.Methods One hundred and two patients with hereditary deafness admitted to the Third Affiliated Hospital of Qiqihar Medical College from January 2014 to May 2016 were enrolled and assigned as the observation group, and another 102 cases with normal hearing were selected as the control group. The gene mutation types and hearing thresholds were detected in the two groups and compared between them, the mutations of alleles 1 and 2 situations of patients with GJB2 and SLC26A4 mutations were analyzed, Ab initio software was used to predict whether there was obstacle preventing the recognition on slice sites, and polymerase chain reaction (PCR) was adopted to detect the common mutation types of SLC26A4 gene.Results In 102 patients with hereditary deafness, the cases caused by SLC26A4 gene mutations were more than those caused by GJB2 gene mutations (30 cases vs. 15 cases). Compared with the normal hearing control group, the mutation rates of GJB2 and SLC26A4 genes were significantly increased in the observation group [GJB2: 14.71% (15/102) vs. 2.94% (3/102), SLC26A4: 29.41% (30/102) vs. 1.96%(2/102), bothP T mutation, indicating that IVS16+10C>T gene mutation was not the cause of genetic deafness.Conclusion There is no obvious relationship between the IVS16+10C>T mutation of SLC26A4 gene and patients with hereditary deafness, which may provide a basis clinically for the prediction of deafness occurrence in the patient's next generation.

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.

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.

Estudo de família brasileira portadora de deficiência auditiva sensorioneural não-sindrômica com herança mitocondrial / Study of a Brazilian family presenting non-syndromic hearing loss with mitochondrial inheritance

O presente estudo teve como objetivo descrever os achados audiológicos e genéticos de nove membros de uma família brasileira que apresenta a mutação no DNA mitocondrial. Todos os nove membros realizaram estudo genético, avaliação foniátrica e audiológica (audiometria tonal e logoaudiometria). O estudo genético revelou a presença de mutação mitocondrial A1555G no gene 12S rRNA (MT-RNR-1) do DNA mitocondrial em todos os sujeitos. Oito sujeitos apresentaram deficiência auditiva e somente um apresentou limiares auditivos normais até o término da realização do estudo. Os resultados audiológicos apontaram para perdas auditivas bilaterais, com prevalência das simétricas, de configurações e graus variados (de moderado a profundo) e pós-linguais. Progressão da perda auditiva foi observada em dois irmãos afetados. Não foi possível afirmar a época do início da perda auditiva por falta de informação dos sujeitos, no entanto, observou-se manifestação da perda em crianças e adultos. As mutações no DNA mitocondrial representam uma causa importante de perda auditiva, sendo imprescindível a realização do diagnóstico etiopatológico, a fim de retardar o início ou evitar a progressão da surdez.

We hereby report on the audiological and genetic findings in individuals from a Brazilian family, with the following mitochondrial mutation A1555G in the 12SrRNA gene (MT-RNR-1). Nine individuals underwent speech, audiologic (tonal audiometry and logoaudiometry) and genetic evaluations. Eight individuals among the A1555G carriers were affected by hearing impairment and one person had normal hearing thresholds till the end of the present study. The audiologic evaluation results indicated normal hearing thresholds all the way to bilateral profound hearing loss with post-lingual onset and variable configuration. Two affected siblings presented progressive hearing loss. It was impossible to precise the time of hearing loss onset; however, the impairment was present in both children and adults. The genetic study revealed the A1555G mitochondrial mutation in the 12SrRNA gene. Given the prevalence of mitochondrial mutations as a cause of hearing loss, it is fundamental to perform the etiopathologic diagnosis in order to postpone the onset or avoid hearing impairment progression. This kind of hearing impairment represents a challenge to the professionals since there are no physical traits that indicate genetic transmission.