Florence Riccardi, Béatrice Desnous, Emilie Borloz, Anne Lepine, Caroline Lacoste, Cécile Mignon‐Ravix, Pierre Cacciagli, Chantal Missirian, Florence Molinari, Jérémie Mortreux, Alexandra Afenjar, Cécilia Altuzarra, Stéphane Auvin, Claire Bar, Magalie Barth, Stéphanie Biscaye, Emilie Bourel-Ponchel, Sébastien Cabasson, Claude Cances, Pierre Castelnau, Isabelle Caubel, Maryline Carneiro, B. Chabrol, Alexandra Chadie, Annabelle Chaussenot, Emmanuel Cheuret, Mondher Chouchane, Benjamin Cogné, Estelle Colin, Florence Démurger, Vincent Desportes, Anne Dieux‐Coëslier, Diane Doummar, Cyril Goizet, Alice Goldenberg, Jamal Ghoumid, Anne-Marie Guerrot, Yvan Herenger, Delphine Heron, Gabriella Horvath, Serge Ilunga, Bertrand Isidor, Médéric Jeanne, Sophie Julia, Anna Kaminska, Emmanuelle Lagrue, Laëtitia Lambert, Anne-Sophie Lèbre, Jérémie Lefranc, Gaëtan Lesca, Virginie Levrat, Hicham Mansour, Isabelle Marey, Stéphane Marret, Hélène Maurey, Julia Métreau, Cyril Mignot, Sophie Naudion, Julien Neveu, Olivier Patat, Laurent Pasquier, Julie Boeswillwald Perrier, Florence Petit, Anne‐Lise Poulat, Chloé Quēlin, Christian Richelme, Paul Rollier, Stéphane Rondeau, Agathe Roubertie, Elise Schaefer, Anne De Saint-Martin, Christel Thauvin, Stéphanie Torre, Annick Toutain, Rudy Van Coster, Dorothée Ville, Nathalie Villeneuve, Laurent Villard, Mathieu Milh
BACKGROUND AND OBJECTIVES: genes are recognized as major causes, the full genetic spectrum remains uncertain. We aimed to delineate the electroclinical characteristics, genetic etiologies, and long-term outcomes in a large MRI-negative EIDEE-BS cohort. METHODS: , "other pathogenic variants," and "without a genetic diagnosis." EEG traces were reviewed independently, and outcomes were assessed through long-term follow-up. RESULTS: ). Most variants were de novo heterozygous; however, recessive and X-linked inheritance patterns were also observed. Mortality was high (25%), primarily from status epilepticus and complications of severe disability. Most patients (72.5%) had persistent seizures at follow-up (a mean of 6.5 years), as well as profound intellectual disabilities, irrespective of genotype. DISCUSSION: were the most commonly affected genes. Early EEG features, particularly BS timing and morphology, can help anticipate the underlying genotype and guide precision therapy, including the early use of sodium channel blockers in selected cases. These findings support recent ILAE reclassification efforts and underscore the importance of comprehensive genomic testing for improved diagnosis and counseling.