Furthermore, regulatory proteins involved in iron metabolism, including iron-regulated protein (IRP)/iron response element (IRE) (Lee and Hyun, 2023), transferrin(Tf)/transferrin receptor(TfR), and ceruloplasmin (CP) (Liu L. et al., 2023) are abnormally expressed or dysfunctional in PD patients. This evidence concerns the gene WNT2 and Parkinson disease.