Familial SCN1A missense mutation over three generations, from febrile seizures to severe myoclonic epilepsy in infancy

摘要: Mutations of the sodium channel alpha subunit type 1 gene (SCN1A) gene, encoding voltage gated alpha-subunit, represent most frequent genetic cause severe myoclonic epilepsy in infancy (SMEI). So far over 250 SMEI related SCN1A mutations have been identified which 95% are considered de novo. We report a familial missense mutation three generations with extremely variable phenotypes, from simple febrile seizures to SMEI. Severe (SMEI) or Dravet syndrome is an age-dependent epileptic en- cephalopathy onset during first year life. Common manifestations disorder often pro- longed hemiclonic generalized tonic-clonic seizures, usually associated fever, previously healthy in- fants normal psychomotor development. Inter- ictal electroencephalography (EEG) shows no sign activity early course disease. The condition evolves variety afebrile fever- induced seizure types (myoclonic, atonic, absence and partial seizures) second Develop- mental stagnation occurs many children showing ataxia slowing speech development; cognitive outcome poor high risk retarda-