LCN2 has been linked to cognitive impairment (Dekens et al., 2021; Olson et al., 2021), and increased LCN2 levels have been observed in patients and mouse model of AD (Kang et al., 2021), as well as in the postmortem brain of patients with mild cognitive impairment (Choi et al., 2011). Here, LCN2 is linked to Alzheimer disease.