Severe epilepsy is often caused by gene mutations. In most patients, the genetic cause cannot be identified. Here, we will focus on the non-coding genome, to find alterations that might lead to epilepsy, located outside protein-coding genes. Mutations in such regulatory elements are known to cause disease, but have not been studied in epilepsy. We will change this, using novel technology and stem cell disease modelling. This will increase our knowledge on how epilepsy originates, will lead to new diagnostics and might on the long term lead to novel therapies.