广州地区非综合征性聋儿家庭的耳聋基因诊断研究

Study on diagnosis of deafness genes in families with children with nonsyndromic hearing loss in Guangzhou

目的:应用耳聋基因芯片结合基因测序法对非综合征性聋儿进行分子病因学研究。方法:收集该地区门诊散发的双侧均为中至极重度非综合征型耳聋家系35个,包括35例聋儿和72例家属,签署知情同意书并填写耳聋调查问卷。抽取外周静脉血运用耳聋基因芯片检测中国人群中常见的4个耳聋基因的9个突变位点,用测序法对6例颞骨CT证实为前庭水管扩大者(enlarged vestibular aqueduct,EVA)及其父母进行SLC26A4全基因序列筛查。结果:35例聋儿中检出常见耳聋基因突变13例,突变率37.1%,其中GJB2基因235delC纯合突变2例、杂合突变2例,299delAT杂合突变1例;线粒体12S rRNA A1555G均质型突变型1例;SLC26A4基因IVS7-2 A>G杂合突变5例;双杂合突变2例:GJB2 235delC/IVS7-2A>G和IVS7-2A>G/mtDNA A1555G。6例EVA患儿SLC26A4基因全序列筛查发现1例1229C>T纯合突变,5例双杂合突变。结论:基因芯片法结合基因测序法能进一步明确患儿的分子致病机制及其遗传方式,为已生育聋儿的家庭再生育提供遗传咨询和产前指导。

Objective To conduct a molecular etiological study on children with nonsyndromic hearing loss （NSHL） by deafnessgene chip combined with gene sequencing. Methods： Peripheral blood specimens were collected from 35 sporadical families of moderate andsevere NSHL （including 35 children and 72 parents） in clinics in Guangzhou. A deafness questionnaire was filled in; peripheral blood samples were abstracted to detect 9 mutation sites of four associated genes by gene chip technique, gene sequencing was used to conduct wholeSLC26A4 gene sequence screening among 6 children diagnosed as enlarged vestibular aqueduct （EVA） by temporal bone CT scanning andtheir parents. Results： Among 35 patients, 13 children were found with common deafness gene mutation, the mutation rate was 37.1%,including 2 children with 235delC homozygous mutation of GJB2 gene, 2 children with heterozygous mutation, one child with 299delAT het-erozygous mutation, one child with mitochondrial 12S rRNA A1555G heterozygous mutation, 5 children with IVS7 -2 A 〉 G heterozygousmutation of SLC26A4 gene, 2 children with double heterozygous mutations （GJB2 235delC/IVS7 -2A 〉 G and IVS7- 2A 〉 G/mtDNAA1555G） ; among six EVA children, one child with 1229C 〉 T homozygous mutation and five children with double heterozygous mutationswere detected by whole SLC26A4 gene sequence screening. Conclusion： Gene chip combined with gene sequencing technology can furtherconfirm the molecular pathogenic mechanism and inheritance mode, which provides genetic counseling and prenatal guidance for re - birth offamilies with a deafness child.