Mutations in Munc18-1 (encoded by the STXBP1 gene) cause a variety of neurodevelopmental disorders known collectively as STXBP1 encephalopathies.1,2 STXBP1 encephalopathies include severe early-onset epileptic encephalopathies3-5 as well as non-syndromic epilepsies, atypical Rett syndrome and severe intellectual disability without epilepsy.6-9 These devastating and often fatal infantile encephalopathies are all characterized by intellectual disability and cerebral dysfunction, and most...
