Sudden unexpected death in epilepsy (SUDEP) is the most common epilepsy-related cause of death. SUDEP is characterised by a sudden, unexpected, and non-traumatic death in a patient with epilepsy, where the post-mortem does not reveal a cause of death. The underlying cause of SUDEP remains unknown. There is emerging evidence that changes in our DNA (genes) found in the heart and brain, may be a key underlying cause of SUDEP. The proposed genetic study will be of benefit to surviving family members, both in terms of earlier diagnosis, closer clinical surveillance and initiation of early therapies to prevent the occurrence of SUDEP.