1. From the Hospital for Sick Children and Research Institute, Toronto, Canada (R.M.H.); Pediatrics (Cardiology) and Translational Medicine, University of Toronto, Canada (R.M.H.); The Ontario Forensic Pathology Service, Toronto, Canada (K.C.); and Cardiology Clinical Academic Group, Molecular and Clinical Sciences Research Institute, St George’s University of London, United Kingdom (E.B.).