STX1B encodes syntaxin-1B, a presynaptic protein that mediates synaptic vesicle docking and fusion at the active zone through SNARE complex formation 1. The protein regulates neurotransmitter release by controlling calcium-dependent exocytosis and interacts functionally with STXBP1-encoded proteins essential for synaptic transmission 2. STX1B mutations cause a diverse spectrum of epilepsy syndromes spanning from benign febrile seizures to severe developmental encephalopathies. Loss-of-function mutations typically produce milder phenotypes with good drug responsiveness, while missense variants in the SNARE motif associate with intractable seizures, developmental regression, and neuropsychiatric complications 3. The most common association is generalized epilepsy with febrile seizures plus (GEFS+) 4, though variants also cause myoclonic-astatic epilepsy and other focal epilepsies 2. Functional studies in zebrafish with stx1b knockdown demonstrate seizure-like behavior and temperature-sensitive epileptiform discharges, with wild-type human syntaxin-1B but not mutant protein rescuing these deficits 1. Beyond neurology, STX1B polymorphisms show association with Parkinson's disease susceptibility 5. Recent structural studies define STX1B protein interaction interfaces relevant to disease pathogenesis 6.