Mutations of the TMPRSS6 gene, that causes defective MT2 at the level of proteolytic domain making the protein not able to appropriately process HJV, lead to a hepcidin excess and an anemia refractory to oral iron treatments named iron Refractory Iron Deficiency Anemia (IRIDA).15, 16, 17. Here, TMPRSS6 is linked to anemia (phenotype).