On the other hand, iron deficiency anemia (IDA) is defined by low serum ferritin (<30 ng/mL without inflammation and <100 ng/mL with inflammation) and low transferrin saturation (<20%) in addition to low Hb levels (<13.5 g/dL for men and <12 g/dL for women) [8]. The gene discussed is GSTM1; the disease is anemia.