KCNQ3 encodes a pore-forming subunit of voltage-gated potassium (Kv7) M-channels that controls neuronal excitability 123. KCNQ3 assembles with KCNQ2 as heterotetramers to form functional channels, though evidence suggests flexible stoichiometry allowing homomeric composition in some neurons 415. The M-current produced exhibits slowly activating/deactivating potassium conductance that regulates subthreshold neuronal excitability and synaptic responsiveness 413. The channel shows preferential K+ permeability (K+ > Rb+ > Cs+ > Na+) and can be modulated by muscarinic acetylcholine receptor activation 36. Pathogenic KCNQ3 variants cause a spectrum of neurodevelopmental disorders ranging from benign familial neonatal seizures to severe developmental and epileptic encephalopathies 789. Loss-of-function and gain-of-function mutations impair channel gating through distinct mechanisms affecting voltage-sensor movement 9. Kv7.2/7.3 channel activation represents a validated therapeutic target; multiple Kv7 activators (including azetukalner and pynegabine) are in clinical development for seizure management 1011. Emerging evidence demonstrates that polyunsaturated fatty acids can functionally restore certain KCNQ3 mutations, suggesting novel therapeutic approaches 9.