What is the most common monogenic cause of epilepsy? This is a question we often ask students and trainees who rotate with us in our Epilepsy Neurogenetics Clinic. This is not meant to be a trick question, and the answer we previously sought was based largely on published studies, estimates of population frequency of individual genetic epilepsies, and our own clinical experience. And we are sometimes surprised by how skewed such a view can be. Now, a new study by Symonds and colleagues answers the question of population-incidence of common genetic epilepsy syndromes through a prospective population-based cohort study in Scotland. This study provides important data on risk factors that are more likely to predict a genetic diagnosis in infants and young children with seizures and answers the question of which genetic epilepsy is most common. I was initially surprised, but really not surprised at all, by the answer. Continue reading →