Molecular Autopsy in Young Individuals With Sudden Cardiac Death

The goal of this observational study is to create and test a pilot workflow for molecular autopsy (genetic testing after death) in children and adults aged 1 to 50 years who died suddenly from an unexplained cause and were examined at the Death Verification Service of the city of São Paulo, Brazil. The main questions it aims to answer are: * How often can a genetic cause of sudden death be found in young people in Brazil? * Can first-degree relatives who carry the same genetic change be identified and referred for heart screening before they have symptoms? Sudden cardiac death in young people is often caused by inherited heart diseases, such as heart rhythm disorders and diseases of the heart muscle. Death may be the first sign of the disease in a family. Most of what is known comes from studies in North America, Europe and Australia, and there are no such data for the Brazilian population. After a family member gives consent, the researchers will: * Interview the family using a verbal autopsy questionnaire and review the autopsy report and death certificate * Collect blood or tissue during the autopsy for genetic testing (whole exome sequencing) * Examine the heart under the microscope When a genetic cause is found, the results will be given to the responsible family member, and first-degree relatives (parents, siblings and children) will be invited to take part. Relatives who agree will give a small blood sample (about 10 mL) to test for the same genetic change. Relatives who carry the change will be referred for heart screening.

Index cases Inclusion Criteria: * Male or female, aged 1 to 50 years at the time of death * Unexplained sudden death, defined as an unexpected, non-traumatic death occurring within 1 hour of symptom onset in an apparently healthy individual or, if unwitnessed, within 24 hours of the individual last being seen alive and asymptomatic * Autopsy performed at the Death Verification Service of the City of São Paulo (SVOC-USP) * Informed consent provided by the legally responsible family member Exclusion Criteria: \- Suspected death from intoxication by toxic substances First-degree relatives Inclusion Criteria: * First-degree relative (parent, sibling or child) of an index case in whom a pathogenic or likely pathogenic variant associated with inherited cardiac disease was identified * Informed consent provided by the participant or, when applicable, by a legal representative