HCN1 and epilepsy: The Hcn1GD/+ and Hcn1MI/+ knock-in mice we generated display not only an appropriate and robust epilepsy phenotype, along with comorbid behavioral abnormalities, but illustrate the difficulties intrinsic to the treatment of genetic developmental epilepsies, including the adverse response of individuals with HCN1 variants to conventional antiseizure medications, and the potential for altered drug sensitivity of mutant channels.