HAMP and Tangier disease: Steinbicker et al. demonstrated that the hepatocyte-specific deficiency of the BMP type I receptor ALK3 not only led to a suppression of basal hepcidin expression and iron overload (mice on a regular diet), but that ALK3 was required for the hepatic hepcidin mRNA induction by iron, BMP ligands and IL-6 [13, 30].