Spectrum and prevalence of cardiac sodium channel variants among black, white, Asian, and Hispanic individuals: Implications for arrhythmogenic susceptibility and Brugada/long QT syndrome genetic testing

Michael J. Ackerman, Igor Splawski, Jonathan C. Makielski, David J. Tester, Melissa L. Will, Katherine W. Timothy, Mark T. Keating, Gregg Jones, Monica Chadha, Christopher R. Burrow, J. Claiborne Stephens, Chuanbo Xu, Richard Judson, Mark E. Curran

Research output: Contribution to journalArticle

232 Scopus citations

Abstract

Objectives. The purpose of this study was to determine the prevalence and spectrum of nonsynonymous polymorphisms (amino acid variants) in the cardiac sodium channel among healthy subjects. Background. Pathogenic mu tations in the cardiac sodium channel gene, SCN5A, cause approximately 15 to 20% of Brugada syndrome (BrS1), 5 to 10% of long QT syndrome (LQT3), and 2 to 5% of sudden infant death syndrome. Methods. Using single-stranded conformation polymorphism, dena turing high-performance liquid chromatography, and/or direct DNA sequencing, mutational analysis of the protein-encoding exons of SCN5A was performed on 829 unrelated, anonymous healthy subjects: 319 black, 295 white, 112 Asian, and 103 Hispanic. Results. In addition to the four known common p olymorphisms (R34C, H558R, S1103Y, and R1193Q), four relatively ethnic-specific polymorphisms were identified: R481W, S524Y, P1090L, and V1951L. Overall, 39 distinct missense variants (28 novel) were elucidated. Nineteen variants (49%) were found only in the black cohort. Only seven variants (18%) localized to transmembrane-spanning domains. Four variants (F1293S, R1512W, and V1951L cited previously as BrS1-causing mutations and S1787N previously published as a possible LQT3-causing mutation) were identified in this healthy cohort. Conclusions. This stud y provides the first comprehensive determination of the prevalence and spectrum of cardiac sodium channel variants in healthy subjects from four distinct ethnic groups. This compendium of SCN5A variants is critical for proper interpretation of SCN5A genetic testing and provides an essential hit list of targets for future functional studies to determine whether or not any of these variants mediate genetic susceptibility for arrhythmias in the setting of either drugs or disease.

Original languageEnglish (US)
Pages (from-to)600-607
Number of pages8
JournalHeart rhythm
Volume1
Issue number5
DOIs
StatePublished - Nov 2004

Keywords

  • Arrhythmia
  • Genetics
  • Ion channels
  • Long QT syndrome
  • Sudden death

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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    Ackerman, M. J., Splawski, I., Makielski, J. C., Tester, D. J., Will, M. L., Timothy, K. W., Keating, M. T., Jones, G., Chadha, M., Burrow, C. R., Stephens, J. C., Xu, C., Judson, R., & Curran, M. E. (2004). Spectrum and prevalence of cardiac sodium channel variants among black, white, Asian, and Hispanic individuals: Implications for arrhythmogenic susceptibility and Brugada/long QT syndrome genetic testing. Heart rhythm, 1(5), 600-607. https://doi.org/10.1016/j.hrthm.2004.07.013