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A 6-month-old previously healthy infant has a prolonged febrile seizure lasting 30 minutes. He goes on to develop multiple seizure types refractory to medications and experiences developmental regression.

AD (de novo); SCN1A (sodium channel α subunit)

  • Onset in first year with prolonged febrile or afebrile seizures
  • Multiple seizure types (myoclonic, absence, focal)
  • Temperature sensitivity (fever, hot baths trigger seizures)
  • Developmental plateau/regression after onset
  • Ataxia, crouched gait

Important: Avoid sodium channel blockers (carbamazepine, phenytoin), which can worsen seizures

  • Suspect Dravet syndrome in an infant with prolonged, fever-triggered hemiclonic or generalized seizures and normal early development, later evolving to multiple drug-resistant seizure types with developmental slowing
  • Confirm with molecular testing of SCN1A (sequencing plus deletion/duplication analysis), usually as part of an epilepsy gene panel
  • Most cases are de novo; the milder GEFS+ phenotypes can be familial (autosomal dominant)
  • EEG is often normal early; molecular testing drives both diagnosis and treatment choice
  • Avoid sodium channel blockers (carbamazepine, phenytoin, lamotrigine), which worsen seizures in SCN1A-related Dravet syndrome
  • First-line agents include valproate and clobazam; stiripentol, fenfluramine, and cannabidiol are approved add-on therapies
  • Aggressive fever and seizure-trigger avoidance; rescue plan and counseling on status epilepticus and SUDEP risk
  • Multidisciplinary developmental, physical, and behavioral support

Think of a "SCeN1c Drive" → SCN1A variants in Dravet

SCN1A/Dravet syndrome mnemonic: "SCeN1c Drive" represents a de novo mutation in Sodium Channel 1A (SCN1A)
SCN1A/Dravet syndrome mnemonic: "SCeN1c Drive" represents a de novo mutation in Sodium Channel 1A (SCN1A)

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