"Mutations in SCN5A may cause sodium channel dysfunction by decreasing peak sodium current, which slows conduction and facilitates reentry based arrhythmias, and by enhancing late sodium current, which prolongs the action potential and sets the stage for early afterdepolarization and arrhythmias."
"The genetic type 3 of this syndrome (LQT3) is caused by gain-of-function mutations in the SCN5A cardiac sodium channel gene which mediates the fast Na v 1.5 current during action potential initiation."
"In addition, sodium channel dysfunction caused by mutations in the SCN5A gene, encoding the major sodium channel in heart, is associated with a number of arrhythmia syndromes."
"Brugada syndrome is an inherited cardiac disorder caused by mutations in the SCN5A gene encoding the cardiac sodium channel alpha subunit, which can lead ventricular fibrillation and sudden death."
"Class I antiarrhythmic agents such as flecainide, lidocaine and mexiletine generally block I (NA (P)) more potently than block of I (Na (T)) and have been used clinically to treat LQT3 syndrome, which arises because mutations in SCN5A produce defective inactivation of the cardiac sodium channel."
"Mutations in KCNQ1 (LQT1) and HERG (LQT2) cause defects in the delayed rectifier potassium currents, [XREF_BIBR XREF_BIBR] whereas mutations in SCN5A (LQT3) cause a persistent cardiac sodium current."
"Since a synonymous nucleotide change in the SCN5A gene is unlikely to induce the functional change of the sodium channel, a non synonymous substitution was considered as a candidate for the mutation associated with this disorder."
"Since a non synonymous nucleotide change in the SCN5A gene is likely to induce a functional change in the sodium channel, a non synonymous substitution was considered a candidate for the variation associated with this disorder."
"As compared to the expression of SCN5A alone, coexpression of both SCN5A and VCL can increase sodium current density by = ~ 30% but did not change the sodium channel 's activation and inactivation properties."
"In addition, sodium channel dysfunction caused by mutations in the SCN5A gene, encoding the major sodium channel in heart, is associated with a number of relatively uncommon arrhythmia syndromes, including long-QT syndrome type 3 (LQT3), Brugada syndrome, conduction disease, sinus node dysfunction, and atrial standstill, which potentially lead to fatal arrhythmias in otherwise healthy young individuals (Tan et al. 2003)."
"In approximately 20% of the cases BrS is caused by mutations in the SCN5A gene on chromosome 3p21-23, encoding the cardiac sodium channel, a protein involved in the control of myocardial excitability."
"Brugada syndrome (BS) is an inherited cardiac disorder associated with a high risk of sudden cardiac death and is caused by mutations in the SCN5A gene encoding the cardiac sodium channel alpha-subunit (Na (v) 1.5)."
"Cardiac sodium channel dysfunction caused by mutations in the SCN5A gene is associated with a number of relatively uncommon arrhythmia syndromes, including long-QT syndrome type 3 (LQT3), Brugada syndrome, conduction disease, sinus node dysfunction, and atrial standstill, which potentially lead to fatal arrhythmias in relatively young individuals."
"175 SQTL3 accounts for approximately 10% of all mutations diagnosed in LQTS, due to changes in the SCN5A gene, whose functional gain produces a continuous sodium input during the plateau phase, which facilitates early depolarization in cardiac cells."
"Mutations in SCN5A have also been shown to cause the sodium channel to turn off prematurely and thus to set the stage for the development of a rapid polymorphic ventricular tachycardia and ventricular fibrillation in patients with the Brugada Syndrome."
"Possible explanations for our case are : (1) the proband but not his father carries unidentified BrS susceptibility gene (s), and/or (2) the father but not the proband carries unknown genetic variant (s) that can rescue or mitigate the BrS phenotype and restore the sodium channel dysfunctions caused by SCN5A gene defects."
"A390V-SNTA1 expressed with SCN5A, nNOS, and PMCA4b in heterologous cells increased peak and late sodium current compared with WT-SNTA1, and the increase was partially inhibited by NOS blockers."
"In contrast we did find a significant increase in expression (~ 2 fold) in Galpha i2 (-/-) mice of the calcium channel alpha subunit, CACNA1C (Ca v 1.2), which underlies the L-type calcium current and SCN5A which underlies the rapidly inactivating sodium current in ventricular myocytes (XREF_TABLE)."