TMPRSS6 and nutritional disorder: Since HFE- and TFR2-related hereditary hemochromatosis (HH) are recessive conditions associated with (low hepcidin induced) iron overload rather than (high hepcidin induced) iron deficiency, these heterozygous variants could theoretically counterbalance the high-hepcidin iron-deficiency phenotype of TMPRSS6-related IRIDA [14,18].