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.

SUDEP stands for sudden unexplained death in epilepsy; a witnessed or unwitnessed, non-traumatic and non-drowning death occurring in benign circumstances, in a person with epilepsy with or without evidence of a seizure and excluding documented status epileptics (seizure duration of 130mins or longer, or seizures without recovery in between), in which a postmortem examination does not reveal a cause of death. SUDEP is not a cause of death so much as it is a descriptive term for a category of unexplained deaths in people with epilepsy or epilepsy-related conditions. Little is known about SUDEP and its mechanisms and risk factors.

One of the main objectives of this study is to investigate the role of various risk factors in the development of sudden unexplained death in patients with epilepsy, with a particular focus on the role of antiepileptic medications. In addition, we want to elucidate the pathophysiologic mechanisms leading to SUDEP.

Inclusion Criteria Sudep Group Subjects diagnosed with epilepsy whose cause of death was sudden and unexplained, and whose families are willing to participate, will be included in the study.

Control Group For the control group, we will include any patient diagnosed with epilepsy currently in the care of the NYU Comprehensive Epilepsy Center, willing and able to participate in the study.

The SUDEP group consists of epileptic patients who had a sudden unexplainable death excluding trauma, drowning, status epilepticus, or other known cause, but there is often evidence of an associated seizure.