GSTM1 and thalassemia: There are an estimated ~ 56,000 annual births globally with severe thalassemia (hemoglobin [Hb] Bart’s hydrops fetalis, Hb H disease, β-thalassemia major, and Hb E/β-thalassemia) [1], though the burden of all clinically significant thalassemia disease likely far exceeds this estimate.