SCN1A encodes the pore-forming alpha subunit of Nav1.1, a voltage-gated sodium channel essential for neuronal excitability and action potential propagation 1. Nav1.1 permits selective sodium ion influx across the neuronal membrane, enabling membrane depolarization and electrical signal propagation while maintaining balanced excitation and inhibition in neural circuits 2. The channel also contributes to mechanically-induced pain perception in somatosensory neurons. SCN1A mutations cause severe developmental epileptic encephalopathies, predominantly Dravet syndrome, accounting for approximately 70% of cases 3. Truncating mutations (frameshift, nonsense, splice-site) and missense mutations affecting conserved ion-pore regions correlate with earlier seizure onset and more severe phenotypes, particularly myoclonic and atypical absence seizures 45. Dravet syndrome presents as fever-triggered generalized seizures beginning in infancy, progressing to multiple seizure types and cognitive impairment by age two 6. Mechanistically, de novo SCN1A mutations cause loss-of-function, with haploinsufficiency as the primary mechanism; recent findings indicate specific interneuron dysfunction underlies disease pathogenesis 78. Interneuron-specific SCN1A gene replacement therapy shows promise in preclinical models, demonstrating potential therapeutic benefit while avoiding adverse effects from ubiquitous expression 8.