In both experimental models of infection, with M. avium and M. tuberculosis, FPN1 expression in the liver was up-regulated [49,61] This up-regulation of FPN1 is probably related to expression in hepatocytes, rather than macrophages, since mice infected with M. avium exhibit iron accumulation inside infected macrophages, in the liver granulomas [62]. The gene discussed is SLC40A1; the disease is infection.