Therefore, we presumed an iron-deficiency anemia in patients with microcytosis and normal CRP if iron, ferritin, and transferrin saturation were not available according to the recommendations of the guidelines of Gasche et al. [14] with the limitation of factors influencing the MCV, especially the use of azathioprine, which can lead to increased MCV. The gene discussed is TF; the disease is Iron deficiency anemia.