SCN11A (sodium voltage-gated channel alpha subunit 11; HGNC:10583, NCBI Gene ID 11280) is a human locus mapped to chromosome band 3p22.2 that encodes voltage-gated sodium channel alpha subunit Nav1.9 (1,791 aa). SCN11A acts in subthreshold persistent sodium current & inflammatory pain sensitization, together with SCN9A (Nav1.7 Channel Gene), SCN10A (Nav1.8 Channel Gene), and Nav1.7 Sodium Channel Protein. Encodes the TTX-resistant Nav1.9 sodium channel generating persistent subthreshold currents in nociceptors.
Subthreshold persistent sodium current & inflammatory pain sensitization
Clinical / Therapeutic Role
Familial episodic pain syndrome type 3 & congenital insensitivity to pain (HSAN7)
Gene Structure & Expression
Genomic Organization & Cytogenetic Locus: 26-exon locus on chromosome 3p22.2 positioned immediately telomeric to SCN10A and SCN5A, encoding a 1,791-amino-acid tetrodotoxin-resistant alpha subunit with unusually slow activation and ultra-slow inactivation kinetics.
Cellular & Tissue Expression Profile: Expressed selectively in unmyelinated C-fiber nociceptors of dorsal root and trigeminal ganglia as well as intrinsic myenteric plexus neurons of the gastrointestinal tract.
Molecular Function & Pathways
Biochemical & Physiological Mechanism: Produces a persistent, non-inactivating TTX-resistant window current near the resting membrane potential (-70 to -40 mV) that depolarizes the nociceptor membrane and lowers the threshold for action potential initiation when potentiated by inflammatory mediators such as prostaglandin E2, bradykinin, histamine, and ATP.
Clinical & Therapeutic Significance
Human Genetic Variants & Disease Phenotypes: Paradoxical severe gain-of-function mutations (such as p.Leu811Pro) depolarize nociceptors so profoundly that Nav1.7 and Nav1.8 undergo chronic inactivation, causing hereditary sensory and autonomic neuropathy type VII (HSAN7) with congenital inability to experience pain, whereas moderate gain-of-function variants cause familial episodic pain syndrome type 3.
Therapeutic & Clinical Pharmacology: Investigated alongside SCN9A and SCN10A for selective isoform-specific channel modulators and AAV-delivered RNA interference targeting chronic inflammatory and visceral pain syndromes.