SCN1A encodes the pore-forming alpha subunit of Nav1.1, a voltage-gated sodium channel that mediates the depolarizing phase of action potentials in excitable membranes. Nav1.1 selectively allows Na+ ions to pass through its pore in response to membrane voltage changes, initiating electrical signal propagation throughout cells and tissues. The channel plays a critical role in regulating neuronal excitability and maintaining the balance between excitation and inhibition in brain neural circuits, with particular importance for inhibitory GABAergic interneurons including parvalbumin-positive and somatostatin-positive neurons 1. Loss-of-function mutations in SCN1A cause a spectrum of epileptic disorders, with truncating mutations associated with earlier onset of severe seizures compared to missense mutations 2. De novo mutations cause severe myoclonic epilepsy of infancy (Dravet syndrome), characterized by fever-induced seizures beginning in the first year of life and subsequent developmental stagnation 3. The mutation spectrum includes not only point mutations but also whole gene deletions, supporting haploinsufficiency as the primary disease mechanism 4. Clinically, SCN1A polymorphisms influence responsiveness to sodium channel blocking antiepileptic drugs like carbamazepine and oxcarbazepine 56. Promising gene therapy approaches using interneuron-specific AAV vectors have shown efficacy in rescuing Dravet syndrome phenotypes in mouse models 7.