Unraveling the phenotypic spectrum of genetic developmental and epileptic encephalopathies

  • Developmental and epileptic encephalopathies (DEE) span a heterogeneous group of phenotypic epileptic genes (SCN1A, SCN2A, SCN8A, SYNGAP1, NEXMIF, CHD2, PCDH19, STXBP1, GRIN2A, KCNT1, KCNQ2 and Angelman syndrome [AS] genes).
  • In a cohort of 510 individuals, DEE genes associated with convulsive status epilepticus (CSE) were SCN1A, KCNT1, and SCN2A. Non-convulsive status epilepticus (NCSE) was found in patients with non-Dravet SCN1A-DEEs, and also in patients with CHD2-DEEs and AS. Sudden unexplained death in epilepsy (SUDEP) was associated with SCN1A, SCN2A, SCN8A, and STXBP1. Of the 8% (42/510) of deaths recorded amongst the cohort, 20 of the 42 cases were attributed to SUDEP, reaching a SUDEP rate of 2.9 per 1,000 person years.
  • Understanding the risks of genetic DEE associated with CSE, NCSE and SUDEP is important in order to develop appropriate strategies for early diagnosis, management and treatment.