Plasma LCN2 concentration was significantly lower in AD (mean: 58.3 ng/ml, SD ± 28.0) compared to both, HC (mean: 105.0 ng/ml, SD ± 53.7, p < 0.001) and MCI-AD (mean: 103.1 ng/ml, SD ± 42.2, p < 0.001) in cohort 1 (Fig. 2A), and compared to HC (mean: 97.6 ng/ml, SD ± 49.0, p = 0.007) in cohort 2 (Fig. 2B). The gene discussed is LCN2; the disease is Alzheimer disease.