HCN2 and idiopathic generalized epilepsy: So far, mutations in HCN2 have been found and characterized in patients with idiopathic generalized epilepsy (IGE; Tang et al., 2008; DiFrancesco et al., 2011), febrile seizures and genetic epilepsy with febrile seizures plus (Dibbens et al., 2010; Nakamura et al., 2013) and GGE (Li et al., 2018).