title: Novel KCNQ1 and HERG missense mutations in Dutch long-QT families.
abstract: Congenital long QT syndrome (cLQTS) is electrocardiographically characterized by a prolonged QT interval and polymorphic ventricular arrhythmias (torsade de pointes). These cardiac arrhythmias may result in recurrent syncopes, seizure, or sudden death. LQTS can occur either as an autosomal dominant (Romano Ward) or as an autosomal recessive disorder (Jervell and Lange-Nielsen syndrome). Mutations in at least five genes have been associated with the LQTS. Four genes, encoding cardiac ion channels, have been identified. The most common forms of LQTS are due to mutations in the potassium-channel genes KCNQ1 and HERG. We have screened 24 Dutch LQTS families for mutations in KCNQ1 and HERG. Fourteen missense mutations were identified. Eight of these missense mutations were novel: three in KCNQ1 and five in HERG. Novel missense mutations in KCNQ1 were Y184S, S373P, and W392R and novel missense mutations in HERG were A558P, R582C, G604S, T613M, and F640L. The KCNQ1 mutation G189R and the HERG mutation R582C were detected in two families. The pathogenicity of the mutations was based on segregation in families, absence in control individuals, the nature of the amino acid substitution, and localization in the protein. Genotype-phenotype studies indicated that auditory stimuli as trigger of cardiac events differentiate LQTS2 and LQTS1. In LQTS1, exercise was the predominant trigger. In addition, a number of asymptomatic gene defect carriers were identified. Asymptomatic carriers are still at risk of the development of life-threatening arrhythmias, underlining the importance of DNA analyses for unequivocal diagnosis of patients with LQTS.
authors.affiliation: Department of Molecular Cell Biology and Genetics, Cardiovascular Research Institute Maastricht, University of Maastricht, The Netherlands. roselie.jongbloed@gen.unimas.nl
authors.forename: R J
authors.initials: RJ
authors.lastname: Jongbloed
authors.forename: A A
authors.initials: AA
authors.lastname: Wilde
authors.forename: J L
authors.initials: JL
authors.lastname: Geelen
authors.forename: P
authors.initials: P
authors.lastname: Doevendans
authors.forename: C
authors.initials: C
authors.lastname: Schaap
authors.forename: I
authors.initials: I
authors.lastname: Van Langen
authors.forename: J P
authors.initials: JP
authors.lastname: van Tintelen
authors.forename: J M
authors.initials: JM
authors.lastname: Cobben
authors.forename: G C
authors.initials: GC
authors.lastname: Beaufort-Krol
authors.forename: J P
authors.initials: JP
authors.lastname: Geraedts
authors.forename: H J
authors.initials: HJ
authors.lastname: Smeets
mesh_terms: D027682:Cation Transport Proteins; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins; D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; D008040:Genetic Linkage; D006239:Haplotypes; D006801:Humans; D051656:KCNQ Potassium Channels; D051657:KCNQ1 Potassium Channel; D008133:Long QT Syndrome / Q000235:genetics*; D018895:Microsatellite Repeats; D020125:Mutation, Missense; D009426:Netherlands; D010375:Pedigree; D011110:Polymorphism, Genetic; D015221:Potassium Channels / Q000235:genetics*; D024642:Potassium Channels, Voltage-Gated; D017386:Sequence Homology, Amino Acid; D015534:Trans-Activators; D000071230:Transcriptional Regulator ERG
chemical_list: D027682:Cation Transport Proteins; D004268:DNA-Binding Proteins; C072312:ERG protein, human; D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; C000606913:KCNH2 protein, human; C092509:KCNH6 protein, human; D051656:KCNQ Potassium Channels; D051657:KCNQ1 Potassium Channel; C496909:KCNQ1 protein, human; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D015534:Trans-Activators; D000071230:Transcriptional Regulator ERG