STXBP1 and early-infantile DEE: Mutations or deletions of STXBP1 have been reported primarily in patients affected with Ohtahara syndrome (2, 3), West syndrome (4), and less frequently in patients affected with early myoclonic epileptic encephalopathy (5, 6), Dravet syndrome (7), Lennox-Gaustaut syndrome (8), Angelman/Pitt Hopkins-like syndrome phenotype (9, 10), and atypical Rett/Rett-like phenotypes (11).