In a murine model for pleiotropic SCN1A-related epilepsy (Scn1aRH±), both prolonged [13] and short [48] exposure to hyperthermia-induced seizures precipitated development of a more severe phenotype than in those without exposure, or in exposed wildtype mice [48], suggesting that febrile seizures and Scn1a haploinsufficiency interact to produce a severe phenotype [48]. The gene discussed is SCN1A; the disease is epilepsy.