Iron replacement strategies [6,7,8,9] with or without erythropoiesis-stimulating agents (ESAs) [10] from several weeks before surgery have been found to be effective in reducing the requirement of transfusion through optimizing the hemoglobin (Hb) level and correcting the iron deficiency in patients undergoing orthopedic surgery. The gene discussed is GSTM1; the disease is Iron deficiency anemia.