TMPRSS6 and anemia: FG‐4592 has been reported to increase endogenous EPO and reduce hepcidin to improve anemia of chronic kidney diseases (CKD) in clinical trials.[32, 33] To further test whether the duodenal HIF‐FPN pathway is also involved in FG‐4592′s effect on anemia of CKD, we randomly assigned Tmprss6‐LKO mice and littermate controls to sham‐operated and 5/6 nephrectomy (5/6Nx) groups to induce anemia of CKD, with or without FG‐4592 treatment (Figure3A).