Red blood cells (RBCs) harbor oxygen-carrying molecules called hemoglobins. RBCs distribute oxygen to every cell of the body, and oxygen is indispensable for mediating the production of cellular fuel called adenosine triphosphate (ATP) in a 3-step process of glycolysis, citric acid cycle, and oxidative phosphorylation. Failure to manufacture a sufficient amount of these hemoglobins would lead to a host of symptoms ranging from shortness of breath and fatigue to organ damage and life-threatening organ failure. These are the exact symptoms experienced by patients of sickle cell anemia, a genetic blood disorder with sickle-shaped RBCs that are dysfunctional at carrying or distributing oxygen to the body. Moreover, the large quantities of sickled RBCs crowd out normal RBCs and interfere with their normal physiological functions. First recognized more than a century ago, there were no breakthroughs or cures until December 8, 2023. On this day of medical significance, the FDA approved Casgevy.16,17
