In 22 % of patients with a serum ferritin between 100 and 800 ng/ml and in 24 % of patients with a serum ferritin ≥ 800 ng/ml iron deficiency anemia was observed (TSAT < 20 %, Hb < 12 g/dl) [27]. The gene discussed is GSTM1; the disease is Iron deficiency anemia.