SCN3B (sodium channel, voltage-gated, type III, beta ,human IgG1-Fc chimera) belongs to the sodium channel auxiliary subunit SCN3B family. It contains 1 Ig-like C2-type (immunoglobulin-like) domain. Voltage-gated sodium channels are transmembrane glycoprotein complexes composed of a large alpha subunit and one or more regulatory beta subunits. They are responsible for the generation and propagation of action potentials in neurons and muscle. SCN3B gene encodes one member of the sodium channel beta subunit gene family, and influences the inactivation kinetics of the sodium channel. Two alternatively spliced variants, encoding the same protein, have been identified. Defects in SCN3B are the cause of Brugada syndrome type 7. A tachyarrhythmia characterized by right bundle branch block and ST segment elevation on an electrocardiogram. It can cause the ventricles to beat so fast that the blood is prevented from circulating efficiently in the body. When this situation occurs (called ventricular fibrillation), the individual will faint and may die in a few minutes if the heart is not reset.