In clinical terms, iron deficiency is often classified as serum ferritin values below <22 μg·L−1, with iron deficiency anemia diagnosed when iron stores are exhausted (serum ferritin <15 μg·L−1), and consequently hemoglobin (Hb) levels fall below 12 g·L−1[6]. Here, GSTM1 is linked to Iron deficiency anemia.