AIM： To map Usher phenotype in a consanguineous Pakistani family and identify disease-associated mutation in a causative gene to establish phenotype-genotype correlation.· METHODS： A consanguineous Pakistani fa...AIM： To map Usher phenotype in a consanguineous Pakistani family and identify disease-associated mutation in a causative gene to establish phenotype-genotype correlation.· METHODS： A consanguineous Pakistani family in which Usher phenotype was segregating as an autosomal recessive trait was ascertained. On the basis of results of clinical investigations of affected members of this family disease was diagnosed as Usher syndrome（USH）. To identify the locus responsible for the Usher phenotype in this family, genomic DNA from blood sample of each individual was genotyped using microsatellite Short Tandem Repeat（STR） markers for the known Usher syndrome loci. Then direct sequencing was performed to find out disease associated mutations in the candidate gene.· RESULTS： By genetic linkage analysis, the USH phenotype of this family was mapped to PCDH15 locus on chromosome 10q21.1. Three different point mutations in exon 11 of PCDH15 were identified and one of them,c.1304AC was found to be segregating with the disease phenotype in Pakistani family with Usher phenotype.This, c.1304 A C transversion mutation predicts an amino-acid substitution of aspartic acid with an alanine at residue number 435（p.D435A） of its protein product.Moreover, in silico analysis revealed conservation of aspartic acid at position 435 and predicated this change as pathogenic.·CONCLUSION：Theidentificationofc.1304ACpathogenic mutation in PCDH15 gene and its association with Usher syndrome in a consanguineous Pakistani family is thefirst example of a missense mutation of PCDH15 causing USH1 phenotype. In previous reports, it was hypothesized that severe mutations such as truncated protein of PCDH15 led to the Usher I phenotype and that missense variants are mainly responsible for non-syndromic hearing impairment.展开更多
The pathogenic factors of deafness are complex;more than 50%of cases are caused by genetic factors.Between 75%and 80%of cases of hereditary hearing impairment are autosomal recessive,15%to 25%are autosomal dominant,an...The pathogenic factors of deafness are complex;more than 50%of cases are caused by genetic factors.Between 75%and 80%of cases of hereditary hearing impairment are autosomal recessive,15%to 25%are autosomal dominant,and 1%to 2%are mitochondrial or X-linked.Cochlea implantation is the main method for treating severe and extremely severe bilateral sensorineural deafness and it is widely used in clinical treatment.As clinical cases of cochlea implantation accumulate,differences in the efficacy of implantation in individuals are emerging and attracting attention.In addition to residual hearing level,implantation age,and other factors,gene mutation is an important factor influencing postoperative rehabilitation in patients.With continuous progress in genetic testing technology for deafness,genetic diagnosis has become an important tool in preoperative evaluation and postoperative effect prediction in patients undergoing cochlear implantation.This article reviews the current status and future development of cochlear implantation in the treatment of hereditary deafness resulting from mutations in common deafness-causing genes.展开更多
目的分析云南省普洱地区傣族、汉族非综合征型耳聋患者GJB2基因编码区核苷酸序列.方法采集同一地区的傣族(20例)、汉族(74例)非综合征型耳聋患者(共94例)及152例健康人群(40例傣族和112例汉族)的外周静脉血,提取基因组DNA,进行GJB2基因...目的分析云南省普洱地区傣族、汉族非综合征型耳聋患者GJB2基因编码区核苷酸序列.方法采集同一地区的傣族(20例)、汉族(74例)非综合征型耳聋患者(共94例)及152例健康人群(40例傣族和112例汉族)的外周静脉血,提取基因组DNA,进行GJB2基因编码区的PCR扩增,并对PCR产物进行测序,检测GJB2基因的突变位点.结果 GJB2基因检测发现了6种常见核苷酸序列的改变方式,包括79G→A、341A→G、109G→A、235delC、608T→C和257-258GC to CG.对照组中未检测到235delC致病突变.在94例非综合征型耳聋患者中发现3例(傣族1例,汉族2例)携带235delC纯合突变(3.19%).其余5种碱基改变为常见的多态性变化.结论相对于中国内地的汉族而言,普洱地区的傣族、汉族非综合征型耳聋患者GJB2基因235delC的突变率较低.展开更多
基金Supported by the Kohat University of Science and Technology,Kohat,PakistanInstitute of Biomedical and Genetic Engineering,Islamabad,Pakistan
文摘AIM： To map Usher phenotype in a consanguineous Pakistani family and identify disease-associated mutation in a causative gene to establish phenotype-genotype correlation.· METHODS： A consanguineous Pakistani family in which Usher phenotype was segregating as an autosomal recessive trait was ascertained. On the basis of results of clinical investigations of affected members of this family disease was diagnosed as Usher syndrome（USH）. To identify the locus responsible for the Usher phenotype in this family, genomic DNA from blood sample of each individual was genotyped using microsatellite Short Tandem Repeat（STR） markers for the known Usher syndrome loci. Then direct sequencing was performed to find out disease associated mutations in the candidate gene.· RESULTS： By genetic linkage analysis, the USH phenotype of this family was mapped to PCDH15 locus on chromosome 10q21.1. Three different point mutations in exon 11 of PCDH15 were identified and one of them,c.1304AC was found to be segregating with the disease phenotype in Pakistani family with Usher phenotype.This, c.1304 A C transversion mutation predicts an amino-acid substitution of aspartic acid with an alanine at residue number 435（p.D435A） of its protein product.Moreover, in silico analysis revealed conservation of aspartic acid at position 435 and predicated this change as pathogenic.·CONCLUSION：Theidentificationofc.1304ACpathogenic mutation in PCDH15 gene and its association with Usher syndrome in a consanguineous Pakistani family is thefirst example of a missense mutation of PCDH15 causing USH1 phenotype. In previous reports, it was hypothesized that severe mutations such as truncated protein of PCDH15 led to the Usher I phenotype and that missense variants are mainly responsible for non-syndromic hearing impairment.
文摘The pathogenic factors of deafness are complex;more than 50%of cases are caused by genetic factors.Between 75%and 80%of cases of hereditary hearing impairment are autosomal recessive,15%to 25%are autosomal dominant,and 1%to 2%are mitochondrial or X-linked.Cochlea implantation is the main method for treating severe and extremely severe bilateral sensorineural deafness and it is widely used in clinical treatment.As clinical cases of cochlea implantation accumulate,differences in the efficacy of implantation in individuals are emerging and attracting attention.In addition to residual hearing level,implantation age,and other factors,gene mutation is an important factor influencing postoperative rehabilitation in patients.With continuous progress in genetic testing technology for deafness,genetic diagnosis has become an important tool in preoperative evaluation and postoperative effect prediction in patients undergoing cochlear implantation.This article reviews the current status and future development of cochlear implantation in the treatment of hereditary deafness resulting from mutations in common deafness-causing genes.
文摘目的分析云南省普洱地区傣族、汉族非综合征型耳聋患者GJB2基因编码区核苷酸序列.方法采集同一地区的傣族(20例)、汉族(74例)非综合征型耳聋患者(共94例)及152例健康人群(40例傣族和112例汉族)的外周静脉血,提取基因组DNA,进行GJB2基因编码区的PCR扩增,并对PCR产物进行测序,检测GJB2基因的突变位点.结果 GJB2基因检测发现了6种常见核苷酸序列的改变方式,包括79G→A、341A→G、109G→A、235delC、608T→C和257-258GC to CG.对照组中未检测到235delC致病突变.在94例非综合征型耳聋患者中发现3例(傣族1例,汉族2例)携带235delC纯合突变(3.19%).其余5种碱基改变为常见的多态性变化.结论相对于中国内地的汉族而言,普洱地区的傣族、汉族非综合征型耳聋患者GJB2基因235delC的突变率较低.
