PRRT2 and idiopathic generalized epilepsy: In this study, we aim to widen the spectrum of phenotypes associated with PRRT2 mutations and investigate whether PRRT2 mutations are involved in febrile seizure-related epilepsy, including febrile seizures plus (FS+), generalized epilepsy with febrile seizures plus (GEFS+) and Dravet syndrome (DS).