Epilepsy Course and Developmental Trajectories in STXBP1-DEE

none58noBackground and Objectives Clinical manifestations in STXBP1 developmental and epileptic encephalopathy (DEE) vary in severity and outcome, and the genotypic spectrum is diverse. We aim to trace the neurodevelopmental trajectories in individuals with STXBP1-DEE and dissect the relationship between neurodevelopment and epilepsy. Methods Retrospective standardized clinical data were collected through international collaboration. A composite neurodevelopmental score system compared the developmental trajectories in STXBP1-DEE. Results Forty-eight patients with de novo STXBP1 variants and a history of epilepsy were included (age range at the time of the study: 10 months to 35 years, mean 8.5 years). At the time of inclusion,65% of individuals (31/48) had active epilepsy, whereas 35% (17/48) were seizure free, and 76% of those (13/17) achieved remission within the first year of life. Twenty-two individuals (46%) showed signs of developmental impairment and/or neurologic abnormalities before epilepsy onset. Age at seizure onset correlated with severity of developmental outcome and the developmental milestones achieved, with a later seizure onset associated with better developmental outcome. In contrast, age at seizure remission and epilepsy duration did not affect neurodevelopmental outcomes. Overall, we did not observe a clear genotype-phenotype correlation, but monozygotic twins with de novo STXBP1 variant showed similar phenotype and parallel disease course. Discussion The disease course in STXBP1-DEE presents with 2 main trajectories, with either early seizure remission or drug-resistant epilepsy, and a range of neurodevelopmental outcomes from mild to profound intellectual disability. Age at seizure onset is the only epilepsy-related feature associated with neurodevelopment outcome. These findings can inform future dedicated natural history studies and trial design.noneGanna Balagura, Julie Xian, Antonella Riva, Francesca Marchese, Bruria Ben Zeev, Loreto Rios, Deepa Sirsi, Patrizia Accorsi, Elisabetta Amadori, Guja Astrea, Simona Baldassari, Francesca Beccaria, Antonella Boni, Mauro Budetta, Gaetano Cantalupo, Giuseppe Capovilla, Elisabetta Cesaroni, Valentina Chiesa, Antonietta Coppola, Robertino Dilena, Raffaella Faggioli, Annarita Ferrari, Elena Fiorini, Francesca Madia, Elena Gennaro, Thea Giacomini, Lucio Giordano, Michele Iacomino, Simona Lattanzi, Carla Marini, Maria Margherita Mancardi, Massimo Mastrangelo, Tullio Messana, Carlo Minetti, Lino Nobili, Amanda Papa, Antonia Parmeggiani, Tiziana Pisano, Angelo Russo, Vincenzo Salpietro, Salvatore Savasta, Marcello Scala, Andrea Accogli, Barbara Scelsa, Paolo Scudieri, Alberto Spalice, Nicola Specchio, Marina Trivisano, Michal Tzadok, Massimiliano Valeriani, Maria Stella Vari, Alberto Verrotti, Federico Vigevano, Aglaia Vignoli, Ruud Toonen, Federico Zara, Ingo Helbig, and Pasquale StrianoGanna Balagura, Julie Xian, Antonella Riva, Francesca Marchese, Bruria Ben Zeev, Loreto Rios, Deepa Sirsi, Patrizia Accorsi, Elisabetta Amadori, Guja Astrea, Simona Baldassari, Francesca Beccaria, Antonella Boni, Mauro Budetta, Gaetano Cantalupo, Giuseppe Capovilla, Elisabetta Cesaroni, Valentina Chiesa, Antonietta Coppola, Robertino Dilena, Raffaella Faggioli, Annarita Ferrari, Elena Fiorini, Francesca Madia, Elena Gennaro, Thea Giacomini, Lucio Giordano, Michele Iacomino, Simona Lattanzi, Carla Marini, Maria Margherita Mancardi, Massimo Mastrangelo, Tullio Messana, Carlo Minetti, Lino Nobili, Amanda Papa, Antonia Parmeggiani, Tiziana Pisano, Angelo Russo, Vincenzo Salpietro, Salvatore Savasta, Marcello Scala, Andrea Accogli, Barbara Scelsa, Paolo Scudieri, Alberto Spalice, Nicola Specchio, Marina Trivisano, Michal Tzadok, Massimiliano Valeriani, Maria Stella Vari, Alberto Verrotti, Federico Vigevano, Aglaia Vignoli, Ruud Toonen, Federico Zara, Ingo Helbig, and Pasquale Strian