Conflict-of-interest disclosure: M.R.A. reports research support from Agios, Novartis Pharmaceuticals, Pfizer, AstraZeneca, Salix Pharmaceuticals, and Novo Nordisk; serves as a member of the data safety monitoring boards for trials with Vertex and CRISPR Therapeutics; reports direct speaker honoraria from Emmaus and Novo Nordisk;travel support from Roche; and serves as a member on the advisory board of Agios Pharmaceuticals. B.A. served as a consultant of Accordant, Afimmune, Agios, Beam Therapeutics, bluebird bio, Chiesi, Editas, Genentech, GlaxoSmithKline, Hema Biologics, Hemanext, Merck, Novartis, Novo Nordisk, Octapharma, Pfizer, Roche, Sanius Health, Sanofi Genzyme, and Vertex; reports research support from Afimmune, Agios, American Society of Hematology, American Thrombosis Hemostasis Network, Centers for Disease Control, Connecticut Department of Public Health, Hemanext, Health Resources and Services Administration, Novo Nordisk, Patient-Centered Outcomes Research Institute, and Pfizer; and served as a member of the data safety monitoring boards for trials with Editas and Fulcrum Therapeutics.