At baseline, patients with iron overload had a mean hepcidin concentration of 110.3 ng/mL (above the upper limits of normal of 85.6 ng/mL [male patients] and 47.3 ng/mL [female patients]), and patients without iron overload had a mean hepcidin concentration of 60.5 ng/mL, which is below the upper limit of normal for male patients (Figure 2b). Here, HAMP is linked to Tangier disease.