Interestingly, the variability in the severity of epilepsy and cognitive impairment in EFMR is reminiscent of what is observed in GEFS+ families (generalized epilepsy with febrile seizures plus, # MIM# 604233), an autosomal dominant condition that also associates febrile seizures with epilepsy of variable types and severity, and which is associated in ∼10–15% of the families with missense mutations in SCN1A[10]. This evidence concerns the gene SCN1A and idiopathic generalized epilepsy.