Focal onset seizures can be caused by multiple different things, for example a malformation in the brain or an injury to the brain. Other causes could be a genetic or metabolic disorder which affects how the brain works, or causes a buildup of toxic materials, or is preventing the brain from getting what it needs. Many seizures or epilepsies are considered idiopathic, which means they have no known cause. We are learning more about them and why they happen, and as we do more testing, we find explanations to previous mysteries, often caused by genetic mutations.