It is known that arginine metabolism is dysregulated in thalassemia (Jain and Lim, 2001), while increased arginase-1 expression (currently observed in β+ versus β++) and activity, in parallel with low l-arginine levels have been linked to oxidative stress and hemolysis (Morris et al., 2017; Contreras-Zentella et al., 2019). The gene discussed is ARG1; the disease is thalassemia.