长QT综合征KCNQ1基因突变筛查方法  

The mutation scanning of KCNQ1 gene for 31 long QT syndrome families

作　　者：李萍[1] 李翠兰[1] 胡大一[1] 刘文玲[1] 秦绪光[2] 李运田[1] 李志明[1] 李蕾[1] 

机构地区：[1]北京大学人民医院心内科,100044 [2]北京酒仙桥医院心内科

出　　处：《中华医学遗传学杂志》2004年第3期236-239,共4页Chinese Journal of Medical Genetics

基　　金：国家自然科学基金 (30 1 70 381 )~~

摘　　要：目的　研究中国人长 QT综合征 ( long QT syndrome,L QTS)与编码缓慢激活延迟整流钾通道基因 ( postassium voltage- gated channel,KQT- like subfamily member1,KCNQ1)突变的关系。方法　根据心电图 T波的特征对 31个家系进行基因分型的初步预测。对 10个预测为 L QT1家系的家庭成员 ,用聚合酶链反应 -单链构像多态性 ( polymerase chain reaction- single strand conformation polymorphism,PCR- SSCP)方法进行KCNQ1基因 16个外显子及剪接位点的筛查 ,SSCP异常者进行 DNA测序。为避免遗漏心电图表现不典型的 L QT1,同时也为了进行方法学比较 ,对其它 2 1个非 L QT1家系只对先证者进行16个外显子的 PCR和 DNA直接测序。对测序有异常者 ,分析其家系成员相应外显子的疾病分离情况。若异常只存在于患者 ,则检查该异常在 5 0个正常对照者中的情况。结果　 ( 1)在心电图预测分型为 L QT1的家系中发现了位于第 5外显子的 S2 77L( 1个家系 )和 G30 6 V( 1个家系 ) 2个错义突变。另外发现了 3个多态性 ,分别为 4 35 C→ T( I14 5 I) ( 7个家系 )、16 32 C→ A ( S5 4 6 S) ( 1个家系 )、IVS1+9C→ G ( 3个家系 )。( 2 )在心电图分型预测为非 L QT1的先证者中只发现了 1个剪接突变 IVS1+5 G→A( 2个家系 )和 1?Objective To search for the mutations of postassium voltage-gated channel, KQT-like subfamily member 1(KCNQ1) gene in 31 Chinese long QT syndrome(LQTS) families. Methods Due to the genetic heterogeneity, the genotype of patients was first predicted based on the spectrum of ST-T-wave patterns on ECG. Ten of 31 probands were considered as LQT1. Then the mutation of KCNQ1 gene was screened by the polymerase chain reaction and single strand conformation polymorphism (PCR-SSCP) technique combined with DNA sequencing in all members of these 10 families. To avoid omitting some LQT1 patients without typical characteristics and also to do methodological comparison, the mutations of KCNQ1 gene on 16 exons were screened by PCR and direct DNA sequencing in the rest 21 non-LQT1 probands only. Co-segregation analysis was carried out after the finding of an abnormal sequence. In case that the abnormality existed in patients only, the test of such exon was performed in 50 irrelevant normal individuals. Results Two missense mutations and three single nucleotide polymorphisms (SNPs) were found in the LQT1-predicted families. The two mutations were S277L (1 family) and G306V (1 family) in exon 5 and were not reported previously. Three polymorphisms were 435C→T (7 families), 1632C→A (1 family), and IVS1+9 C→G (3 families). Only a splice mutation IVS1+5G→A (2 families) and a polymorphism IVS10+18C→T (1 family) were found in the non-LQT1-predicted probands. All three mutations were localized within the functional domain of KCNQ1 and were co-segregated with the disease, and were not found in 50 normal individuals. Conclusion Two novel missense mutations, 1 splice mutation and four SNPs on KCNQ1 gene were found in the 31 LQTS families. Combined with ECG-based genotype prediction, PCR-SSCP could find most mutations on KCNQ1 and be a simple and economic method for screening LQTS.

关 键 词：长QT综合征 缓慢激活延迟整流钾通道基因 基因突变 心电图 T波 聚合酶链反应 单链构像多态性 

分 类 号：R541.7[医药卫生—心血管疾病]