1. Cardiovascular Division, Brigham and Women’s Hospital, Boston, MA (C.Y.H., A.L.C., N.K.L.).
2. Department of Internal Medicine, University of Michigan, Ann Arbor (S.M.D., A.S.H., C.E.S.).
3. Stanford Center for Inherited Heart Disease, CA (E.A.A., C.A.C.).
4. Department of Cardiology, Thoraxcenter, Erasmus Medical Center Rotterdam, the Netherlands (M.M.).
5. Heart Institute (InCor), University of Sao Paulo Medical School, Brazil (A.C.P.).
6. Yale University, New Haven, CT (D.J.).
7. MyoKardia, Inc, South San Francisco, CA (J.D.F., E.M.G.).
8. National Heart and Lung Institute and National Institute for Health Research Royal Brompton Cardiovascular Biomedical Research Unit, Imperial College London, United Kingdom (J.S.W.).
9. Department of Cardiology, Boston Children’s Hospital, MA (S.D.C.).
10. Cardiomyopathy Unit and Genetic Unit, Careggi University Hospital, Florence, Italy (F.G., F.C., I.O.).
11. Howard Hughes Medical Institute, Chevy Chase, MD (C.E.S.).
12. Analysis Group Inc, Boston, MA (G.S., J.S.).