An evaluation of the mechanism of ERFE’s regulation of hepcidin demonstrates that ERFE sequesters BMP2 and BMP6, resulting in decreased BMP:BMPR binding, decreased BMP:SMAD signaling, and decreased hepcidin expression (Arezes et al., 2018; Wang et al., 2020; Figure 4A and B), increasing iron absorption and release from intracellular iron stores to meet the iron requirements of temporarily expanded erythropoiesis during recovery from transient anemia. Here, HAMP is linked to anemia (phenotype).