Molecular variants in the SCN9A gene (MIM#603415) are responsible for a range of seizure disorders, which are characterized by early-onset isolated febrile seizures to generalized epilepsy with febrile seizures plus, type 7 (GEFS+), which identifies the most severe phenotype, as well as primary erythermalgia, callousness to pain linked to channelopathy and extreme paroxysmal pain disorder. The gene discussed is SCN9A; the disease is idiopathic generalized epilepsy.