HAMP and anemia (phenotype): It was noticed that the levels of serum GDF-15 are significantly higher in children with CKD, which may be due to GDF-15 having a negative feedback mechanism that suppresses elevated levels of hepcidin in patients with CKD and anemia may be attributed to the stimulation of GDF-15 production in red blood cells, which occurs as a consequence of iron deficiency in macrophages, these macrophages are activated with pro-inflammatory cytokines which increased in case of CKD9.