Blood work showed red blood cell (RBC) count, 4.51×1012/L with 0.82 % reticulocytes; Hb, 9.9 g/dL; hematocrit (Ht), 32.5 %; and MCV, 72.1 fL. Serum iron, 21 μg/dL; total iron binding capacity, 518 μg/ dL; and ferritin, 8.7 ng/mL, following the diagnosis of iron deficiency anemia. The gene discussed is GSTM1; the disease is Iron deficiency anemia.