title: Genetic Variation of SCN5A in Korean Patients with Sick Sinus Syndrome.
abstract: OBJECTIVE
  Due to recent studies that have shown an association between the genetic variation of SCN5A and sick sinus syndrome (SSS), we sought to determine if a similar correlation existed in Korean patients with SSS.
  
  
  METHODS
  We enrolled 30 patients with SSS who showed a sinus pause (longer than 3.0 s) in Holter monitoring, in addition to 80 controls. All exons including the putative splicing sites of the SCN5A gene were amplified by polymerase chain reaction and sequenced either directly or following subcloning. Wild-type and single nucleotide polymorphisms were expressed in human embryonic kidney cells, and the peak sodium current (INa ) was analyzed using the whole-cell patch-clamp technique.
  
  
  RESULTS
  A total of 9 genetic variations were identified: 7 variations (G87A-A29A, IVS9-3C>A, A1673G-H558R, G3823A-D1275N, T5457C-D1819D, T5963G-L1988R, and C5129T-S1710L) had been previously reported, and 2 variants (A3075T-E1025D and T4847A-F1616Y) were novel; the potential structural effects of F1616Y were analyzed in a three-dimensional model of the SCN5A domain. Patch-clamp studies at room temperature demonstrated that the peak INa was significantly increased by 140% in HEK cells transfected with F1616Y compared with wild-type (-335.13 pA/pF±24.04, n=8 vs. -139.95 pA/pF±23.76, n=7, respectively). Furthermore, the voltage dependency of the activation and steady-state inactivation of F1616Y were leftward-shifted compared with wild-type (Vh activation=-55.36 mv±0.22, n=8 vs. Vh activation=-44.21 mV±0.17, n=7; respectively; Vh inactivation=-104.47 mV±0.21, n=7 vs. Vh inactivation=-84.89 mV±0.09, n=12, respectively).
  
  
  CONCLUSIONS
  F1616Y may be associated with SSS.
authors.affiliation: Division of Cardiology, Catholic University of Daegu, Daegu, Korea.
authors.forename: Young Soo
authors.initials: YS
authors.lastname: Lee
authors.affiliation: Krannert Institute of Cardiology, Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Olaopa
authors.affiliation: Daegu Fatima Hospital, Daegu, Korea.
authors.forename: Byung Chun
authors.initials: BC
authors.lastname: Jung
authors.affiliation: Yeungnam University, Daegu, Korea.
authors.forename: Sang Hee
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Yeungnam University, Daegu, Korea.
authors.forename: Dong Gu
authors.initials: DG
authors.lastname: Shin
authors.affiliation: Department of Internal Medicine, Keimyung University, Daegu, Korea.
authors.forename: Hyoung Seob
authors.initials: HS
authors.lastname: Park
authors.affiliation: Kyungpook National University, Daegu, Korea.
authors.forename: Yongkeun
authors.initials: Y
authors.lastname: Cho
authors.affiliation: D&P Biotech, Daegu, Korea.
authors.forename: Sang Mi
authors.initials: SM
authors.lastname: Han
authors.affiliation: D&P Biotech, Daegu, Korea.; Department of Biochemistry and Cell Biology, Kyungpook National University, Daegu, Korea.
authors.forename: Myung Hoon
authors.initials: MH
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Keimyung University, Daegu, Korea.
authors.forename: Yoon Nyun
authors.initials: YN
authors.lastname: Kim
keywords: Polymorphism, single nucleotide; SCN5A protein, human; Sick sinus syndrome