Hfe is important for the control of hepcidin in response to iron in β-thalassemic mice. Expression of Hamp (A), Bmp6 (C), and Id1 (E) in the liver of wt and thalassemic mice at 5 months of age. Values for wt → wt (wt mice engrafted with wt HSCs), th3 → wt (wt mice engrafted with th3/+ HSCs), and th3 → Hfe-KO (Hfe-KO mice engrafted with th3/+ HSCs) mice are shown. Expression levels of Hamp, Bmp6, and Id1 were normalized to liver iron concentrations and are shown in panels B, D, and F, respectively. All of these genes are abnormally low in th3 → wt mice considering their iron load but are further down-regulated in th3 → Hfe-KO mice. Data are mean ± SEM of 5 to 8 mice. *P ≤ .05. **P ≤ .01.