Similar early characteristics but variable neurological outcome of patients with a de novo mutation of KCNQ2

Mathieu Milh, Nadia Boutry-Kryza, Julie Sutera-Sardo, Cyril Mignot, Stéphane Auvin, Caroline Lacoste, Nathalie Villeneuve, Agathe Roubertie, Bénédicte Heron, Maryline Carneiro, Anna Kaminska, Cécilia Altuzarra, Gaëlle Blanchard, Dorothée Ville, Marie Anne Barthez, Delphine Heron, Domitille Gras, Alexandra Afenjar, Nathalie Dorison, Dianne Doummar, Thierry Billette de Villemeur, Isabelle An, Aurélia Jacquette, Perrine Charles, Julie Perrier, Bertrand Isidor, Laurent Vercueil, Brigitte Chabrol, Catherine Badens, Gaétan Lesca, Laurent Villard

Early onset epileptic encephalopathies (EOEEs) are dramatic heterogeneous conditions in which aetiology, seizures and/or interictal EEG have a negative impact on neurological development. Several genes have been associated with EOEE and a molecular diagnosis workup is challenging since similar phenotypes are associated with mutations in different genes and since mutations in one given gene can be associated with very different phenotypes. Recently, de novo mutations in KCNQ2, have been found in about 10% of EOEE patients. Our objective was to confirm that KCNQ2 was an important gene to include in the diagnosis workup of EOEEs and to fully describe the clinical and EEG features of mutated patients.