Among APOE-ε4 carriers, there were significant gender differences in QSM values of the bilateral putamen (Right; 95% CI: -0.0208 to -0.0021; P = 0.019), (Left; 95% CI: -0.0166 to -0.0002; P = 0.045) in the AD group (Figure 2G) and of the left caudate nucleus (95% CI: 0.0003 to 0.0148; P = 0.044) in the MCI group (Figure 2H). The gene discussed is APOE; the disease is Alzheimer disease.