Previous studies of genetic variants in hepcidin or hepcidin regulation pathways focused on iron burden; for example, one group found common variants in hepcidin regulation pathways to be associated with penetrance of HFE (hereditary) hemochromatosis penetrance 19, and another group implicated variants in Hamp regulators as well 20. The gene discussed is HAMP; the disease is hemochromatosis type 1.