In the substantia nigra of PD models, down-regulated of iron export protein Fpn1 and up-regulated of iron import protein DMT1 and TfR1 were observed, which played critical role in the iron accumulation in the substantia nigra (Kalivendi et al., 2003; Wang et al., 2007; Jiang et al., 2010). The gene discussed is SLC40A1; the disease is Parkinson disease.