Thus, to clarify whether the higher hepcidin values we found were due to impaired iron metabolism (namely, iron overload) or, on the other hand, were already causing iron deficiency, we evaluated three key markers of iron status: ferritin, transferrin and soluble transferrin receptor, which can also provide an assessment of the distal consequences of the elevated hepcidin levels we found. Here, TFRC is linked to Tangier disease.