STXBP1 (syntaxin binding protein 1, also known as Munc18-1) is a critical regulator of synaptic vesicle docking and fusion essential for neurotransmission. The protein functions by binding syntaxins (particularly STX1A) and mediating assembly of the SNARE complex at synaptic membranes, thereby enabling the release of neurotransmitters from neurons 1. STXBP1 also plays roles in platelet granule exocytosis and other regulated secretory processes [GO annotations]. Heterozygous STXBP1 mutations cause developmental and epileptic encephalopathy 4 (DEE4), one of the most common genetic causes of early-onset severe neurodevelopmental disorders 2. Disease mechanisms involve both haploinsufficiency and dominant-negative effects 1. The phenotypic spectrum is broad: 95% of affected individuals have seizures (89% with neonatal or infantile onset, including West syndrome in ~19%), while all have intellectual disability, typically severe to profound 23. Notably, seizure severity and cognitive outcome show no correlation with mutation type 2. STXBP1 variants account for recurrent de novo mutations in autism and developmental delay cohorts 45. Currently, patients receive antiepileptic drugs; however, emerging precision therapeutics including chemical chaperones show therapeutic promise 6.