中国人非综合征型听力损失患者Cx26基因的突变分析

目的 分析中国人遗传性非综合征型听力损失（nonsyndromic hearing impairmetn,NSHI)患者缝隙连接蛋白（connexin 26,Cx26)基因编码区的突变。方法 对天津市聋哑学校的8个聋哑学生的家系中29例以及健康对照2例和有家族史但本人听力正常的遗传咨询者2例共33例取外周血提取DNA，经聚合酶链反应（olymerase chain reaction,PCR)扩增Cx26基因编码区片段，通过限制酶切指纹－单链构像多态性（restriction endonucleases fingerprinting-single strand conformation polymorphism,REF-SSCP)分析法进行突变筛选，经DNA测序判断多态性改变或致病突变。结果 33例中有30例Cx26基因发生改变，改变率为90．91％（30／33），共发现8种不同形式的改变，包括79G→A，109G→A，161A→T，235delC,240G→A,341A→G,571T→Ct 608T→C,其中161A→t,240G→A和571T→C为新发现的突变。22例耳聋患者中有3例为235delC，突变率为13．64％（3／22）。结论 Cx26基因235delC是中国人NSHI患者中主要的突变方式，NSHI患者中存在较多的多态性改变。

Mutation analysis of Cx26 gene in Chinese hereditary nonsyndromic deafness sufferers]

OBJECTIVE: To analyze the mutations in the code region of Cx26 gene in Chinese hereditary nonsyndromic hearing impairment (NSHI) sufferers. METHODS: Thirty-three cases (29 cases in the families of 8 students who were picked out from the Deafness and Muteness School of Tianjin, 2 cases as control and 2 normal cases of genetic counseling) were included in this study. The blood samples were obtained to distill the DNA templates. Using polymerase chain reaction (PCR), the code region of Cx26 gene was amplified. The mutations were screened by restriction endonucleases fingerprinting-single strand conformation polymorphism (REF-SSCP). Afterwards we inspected the polymorphous changes or mutations of these segments with DNA sequence. RESULTS: There were 30 cases with the nucleotide changes in the Cx26 code region. The rate was 90.9% (30/33). Eight kinds of mutations were found, 79G-->A, 109G-->A, 161A-->T, 235delC, 240G-->A, 341A-->G, 571T-->C and 608T-->C. 161A-->T, 240G-->A and 571T-->C were detected primarily. There were 3 cases with 235delC in 22 deafness sufferers and the rate was 13.64% (3/22). CONCLUSIONS: The 235delC of Cx26 gene is the main mutation in Chinese NSHI sufferers, and in NSHI cases many polymorphous changes exist.