While compounds that increase hepcidin reduce ineffective erythropoiesis due to the vicious cycle between ineffective erythropoiesis and iron loading (Camaschella and Nai, 2016), drugs that favor erythroid precursor maturation, as the activin receptor IIB ligand trap, luspatercept, not only improve anemia but also ameliorate iron homeostasis by reducing hepcidin inhibition (Piga et al., 2019). Here, HAMP is linked to anemia (phenotype).