Dravet syndrome
severe myoclonic epilepsy of infancy
A rare disorder (OMIM:607208) characterised by generalised tonic, clonic and tonic-clonic seizures triggered at first by fever and arising shortly after birth. Later, patients also manifest other seizure types, including absence, myoclonic, and simple and complex partial seizures. Psychomotor developmental delay appears by the second year of life. SMEI is the most severe phenotype in the spectrum of generalised epilepsies with febrile seizures-plus.Molecular pathology
Defects of GABRG2, which encodes a subunit of a ligand-gated ionic channel that plays a key role in inhibiting neurotransmission, cause severe myoclonic epilepsy of infancy.