Nav1.5 is the major cardiac voltage-gated sodium channel encoded by SCN5A. It drives the fast inward sodium current underlying phase-0 depolarization in working myocardium and much of the cardiac conduction system.[1][2] Functionally, Nav1.5 determines conduction velocity, excitability reserve, and susceptibility to ventricular and atrial rhythm instability when gating is disturbed.[1:1][3]
Within NeuroWiki, Nav1.5 is important as a channelopathy benchmark: it shows how subtle gating defects, modifier genes, and structural context combine into heterogeneous clinical phenotypes.[3:1][4]
Nav1.5 shares the conserved Nav architecture (DI-DIV, each with S1-S6 segments) but has tissue-specific regulatory context in cardiomyocytes, including interaction with scaffolding and intercalated-disc proteins.[1:2][2:1] Pathogenic variants can alter:
The resulting conduction instability can manifest across a spectrum rather than as isolated monogenic labels.[3:3][4:1]
SCN5A/Nav1.5 dysfunction is classically associated with inherited arrhythmia syndromes, including Brugada-pattern phenotypes, long-QT mechanisms, conduction disease, and overlap presentations.[3:4][4:2][5:1][6]
A major contemporary point is pleiotropy: one variant may map to multiple electrophysiologic outcomes depending on background genetics and cellular environment.[3:5][4:3]
Newer analyses describe broader SCN5A channelopathy scope, including cardiomyopathic and occasional neurologic/epilepsy overlap phenotypes in specific families.[3:6] This does not make Nav1.5 a primary neurodegeneration protein, but it reinforces a shared principle across brain and heart: channel dysfunction is often network disease, not single-parameter disease.[1:4][3:7]
Nav1.5 has limited direct AD/PD causality evidence. Its translational relevance is conceptual and methodological:
Clinical strategy depends on mechanism class rather than the gene label alone:[3:8][4:5]
The key lesson for neurodegeneration translational work: channel-targeted interventions require variant-aware, mechanism-aware trial design.
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Abriel H. Cardiac sodium channel Nav1.5 and its associated proteins. Archives des Maladies du Coeur et des Vaisseaux. 2007. ↩︎ ↩︎
Li W, Yin L, Shen C, Hu K, Ge J, Sun A. The cardiac sodium channel gene SCN5A and its gene product NaV1.5: Role in physiology and pathophysiology. Gene. 2015. ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎
Kapplinger JD, Giudicessi JR, Ye D, et al. Enhanced Classification of Brugada Syndrome-Associated and Long-QT Syndrome-Associated Genetic Variants in the SCN5A-Encoded NaV1.5 Cardiac Sodium Channel. Circulation: Cardiovascular Genetics. 2018. ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎
Ruan Y, Liu N, Priori SG. Sodium channel mutations and arrhythmia. Pediatric Cardiology. 2012. ↩︎ ↩︎ ↩︎
Antzelevitch C, Patocskai B. Brugada Syndrome: Clinical, Genetic, Molecular, Cellular, and Ionic Aspects. Current Problems in Cardiology. 2018. ↩︎