Emerging evidence suggested that blood iron homeostasis is altered in AD and already in MCI (Faux et al., 2014; Ashraf et al., 2020; Guan et al., 2020), including systemic variation of markers of iron metabolism, such as transferrin saturation and ceruloplasmin/transferrin ratio in serum (Squitti et al., 2010). The gene discussed is CP; the disease is Alzheimer disease.