Consistent with the mechanism of action of hepcidin, RARS patients in this study tended to have the highest levels of toxic non–transferrin bound iron (NTBI; 1.59 μM) while levels in the RAEB and CMML patients were lower (0.03 and 0.19 μM, respectively; p = .058; Santini et al., 2011). Here, HAMP is linked to myelodysplastic syndrome with ring sideroblasts.