The main purpose of this study is to develop a North American registry for SUDEP cases; requesting family members of epilepsy patients who died suddenly of unclear causes (SUDEP) to contact the study team. The family members who decide to participate in the study will be asked to complete a brief telephone interview about their loved one's epilepsy and seizure history and the circumstances of his or her death. If the death has occurred within the past 24 hours, and the family is willing to consider donating tissue to the study, the subject will be transferred to the Autism Tissue Program, and the remainder of the phone interview will be conducted at a later time. In addition to the phone interview, the family will be asked to provide access to the deceased's medical records. Any costs involved in obtaining medical records will be covered by the study, and all medical information will remain completely confidential.