Novel mutations in domain I of SCN5A cause Brugada syndrome.
Brugada syndrome, an autosomal dominantly inherited form of ventricular fibrillation characterized by ST-segment elevation in leads V1-V3 and right bundle-branch block on surface electrocardiogram, is caused by mutations in the cardiac sodium channel gene SCN5A. Patients with Brugada syndrome were studied using single-strand conformation polymorphism analysis, denaturing high-performance liquid chromatography, and DNA sequencing of SCN5A. Mutations were identified in SCN5A in two families and one sporadic case. In one family, a missense mutation leading to a glycine to valine substitution (G351V) in the pore region between the DIS5 and DIS6 transmembrane segments was detected. Biophysical analysis demonstrated that this mutation caused significant current reduction. In the other family, a 20-bp deletion of the exon 5 splice acceptor site was identified; as exon 5 encodes part of the intracellular loop between DIS2 and DIS3, this portion of the channel is disrupted. In the sporadic patient, a missense mutation resulting in the substitution of lysine by glutamic acid (K126E) in the intracellular loop at the boundary with DIS1 was identified. These three new SCN5A mutations in Brugada syndrome patients are all located within domain I of SCN5A, a region not previously considered important in the development of ventricular arrhythmias.
Vatta
Matteo
M
Department of Pediatrics (Cardiology), Baylor College of Medicine, Houston, TX, USA.
Dumaine
Robert
R
Antzelevitch
Charles
C
Brugada
Ramon
R
Li
Hua
H
Bowles
Neil E
NE
Nademanee
Koonlawee
K
Brugada
Josep
J
Brugada
Pedro
P
Towbin
Jeffrey A
JA
D000818:Animals; D001483:Base Sequence; D002851:Chromatography, High Pressure Liquid; D017353:Gene Deletion; D006801:Humans; D008564:Membrane Potentials; D008969:Molecular Sequence Data; D009154:Mutation; D020125:Mutation, Missense; D062554:NAV1.5 Voltage-Gated Sodium Channel; D018807:Polymorphism, Single-Stranded Conformational; D017422:Sequence Analysis, DNA; D015222:Sodium Channels / Q000235:genetics* / Q000502:physiology; D013577:Syndrome; D014693:Ventricular Fibrillation / Q000235:genetics* / Q000503:physiopathology; D014981:Xenopus
D062554:NAV1.5 Voltage-Gated Sodium Channel; C568320:SCN5A protein, human; D015222:Sodium Channels