1. Department of Pathology, The Children’s Hospital of Philadelphia and Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
2. Department of Pathology, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts
3. Departments of Pathology, Cardiology, and Cardiac Surgery, Boston Children’s Hospital, Boston, Massachusetts
4. Department of Pediatrics, Harvard Medical School, Boston, Massachusetts
5. Department of Histopathology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK