Analysis of the frequency of clinical signs and association with CKD stage showed that children with CKD stages 4 or 5 (except children after a kidney transplant) had hypertension (87.5%) and anemia (50%) significantly more often and they were prescribed erythropoietin more frequently (37.5%) than those with CKD stages 2 or 3 (Table 5 and Table 6). The gene discussed is EPO; the disease is anemia.