Developmental and Epileptic Encephalopathies (DEEs) represent the most severe form of epilepsy, with onset typically in infancy or childhood. They combine two components:
- Developmental encephalopathy: Often leads to intellectual disability.
- Epileptic encephalopathy: Characterized by epileptic activity that exacerbates cognitive and behavioral impairments beyond the underlying pathology.
Patients with DEEs frequently experience multiple seizure types, accompanied by developmental slowing or regression linked to epileptiform EEG activity. Early diagnosis is crucial as targeted therapies can improve epileptiform activity and potentially foster developmental progress.
The International League Against Epilepsy (ILAE) expanded the definition in 2017 to recognize that DEEs often result from genetic, structural, or other aetiologies that independently cause developmental delays. For example, in Dravet syndrome, developmental delays occur before epileptic activity intensifies the impairment.
DEEs differ from static developmental encephalopathies, where developmental impairments are unrelated to epilepsy. DEEs are classified by epilepsy syndromes, like Lennox–Gastaut syndrome (LGS), which features intellectual disability, characteristic EEG patterns, and diverse aetiologies.
This complex group of disorders profoundly affects patients’ quality of life. Advances in precision medicine offer hope for improved outcomes through tailored therapies.
Among the numerous genetic causes, a subset of DEEs linked to dysfunction in potassium ion channels (K-DEEs) is at the center of the research conducted in the Innov4-ePik program.
Modified from: Scheffer IE, Zuberi S, Mefford HC, Guerrini R, McTague A. Developmental and epileptic encephalopathies. Nat Rev Dis Primers. 2024 Sep 5;10(1):61. doi: 10.1038/s41572-024-00546-6. Erratum in: Nat Rev Dis Primers. 2024 Sep 13;10(1):66. doi: 10.1038/s41572-024-00558-2. PMID: 39237642.
External ressources about DEEs
RHU patient associations:
- KCNB1 France: https://kcnb1-france.org/
- KCNT1 Foundation: https://kcnt1epilepsy.org/
- KCNA2 Epilepsy: https://www.kcna2epilepsy.org/
Partner patient associations:
- KCNH1: https://www.curekcnh1.org/
- EFAPPE: https://www.efappe.epilepsies.fr/
- KCNQ2: https://kcnq2francedeveloppement.fr/
French rare diseases network:
- French reference center for rare epilepsies (CRéER) : https://maladiesrares-necker.aphp.fr/epilepsies-rares/
- Rare diseases platform, AP-HP Université paris cité : https://maladiesrares-necker.aphp.fr/
- Filière DéfiScience : https://defiscience.fr/
European reference network:
- EpiCARE: https://epi-care.eu/
Scientific societies:
- International League Against Epilepsy (ILAE): https://www.ilae.org/
- French league against epilepsy (Ligue Française Contre l’Epilepsie, LFCE): https://www.epilepsie-info.fr/
- French neuropaediatric society (Société Française de neuropédiatrie, SFNP): https://v2.sfneuroped.fr/
Rare diseases information:
- Rare diseases knowledge database, Orphanet : https://www.orpha.net/fr
