In CKD patients with iron deficiency, ferritin levels were significantly lower in the 2–6 year-old age group (44.86 ± 53.08 ng/mL, p < 0.001); however, the lowest age group with transferrin saturation was 0–2 years (21.68 ± 13.51%, p = 0.001) (Table 3). The gene discussed is TF; the disease is chronic kidney disease.