The SCN1A gene encodes the α1 subunit of the voltage-gated sodium channel Nav1.1. critical for neuronal excitability, particularly in inhibitory GABAergic interneurons. Antibodies targeting SCN1A or Nav1.1 are primarily studied in two contexts: autoimmune encephalitis and experimental research tools. In autoimmune neurology, anti-SCN1A antibodies are rare but identified in patients with encephalitis or epilepsy syndromes. These autoantibodies may disrupt Nav1.1 function, impairing inhibitory signaling and causing hyperexcitability, manifesting as seizures, cognitive deficits, or movement disorders. Their detection, often via cell-based assays, aids in diagnosing immune-mediated conditions, though clinical significance requires correlation with symptoms and treatment response. Experimentally, SCN1A-specific antibodies are used to study channel localization, function, and dysfunction in diseases like Dravet syndrome (caused by SCN1A mutations). Research highlights their dual role: pathogenic drivers in autoimmunity and investigative tools for channelopathies. Challenges include confirming pathogenicity and distinguishing them from cross-reactive antibodies. Immunotherapies (steroids, IVIg) may benefit seropositive patients, underscoring the importance of antibody characterization in guiding treatment.