Competing Interests: LHP is funded through the National Institutes of Health (NIH) and National Heart, Lung, and Blood Institute (NHLBI; K23HL146841 and U01 HL156620–01), the American Society of Hematology, Doris Duke Charitable Foundation Grant (2020147), the Mellon Foundation, and Alexion and served as a consultant for Global Blood Therapeutics and Novo Nordisk. CPC serves as a consultant for DimeRx. SL receives research funding from Imara, Novartis, Global Blood Therapeutics, Takeda, CSL-Behring, Health Resources and Services Administration, Patient-Centered Outcomes Research Institiute and Maryland Community Health Resources Commission; consultancy for Bluebird bio, Novo Nordisk, Pfizer, and Magenta; and owns stock in Pfizer and Teva. AMA declares no competing interests. MH has research funding to the institution from Novo Nordisk, consultancy for Bluebird bio, and family member employment at Pfizer. ES has served as a consultant for Bluebird bio. KHMK is funded through NIH and NHLBI (1R33HL147845), Thalassemia Foundation Canada, Peter Munk Cardiac Centre, University of Toronto, Canadian Hematology Society, Agios Pharmaceuticals, and Pfizer and served as a consultant for Alexion Pharmaceuticals, Agios Pharmaceuticals, Bristol Myers Squibb, Forma Therapeutics, Pfizer, Novo Nordisk, and Vertex Pharmaceuticals. DSD serves as consultant for Pfizer, Novonordisk, Novartis, Agios Pharmaceuticals and Bluebird bio.