The MCI-AD group had significantly lower CSF Aβ1-42 concentrations (674.1 ± 176.9 vs. 1,256.6 ± 385.2 pg./mL, p < 0.0001) and Aβ1-42/Aβ1-40 ratios (0.048 ± 0.010 vs. 0.097 ± 0.017, p < 0.0001), as well as significantly higher CSF p-tau concentrations (82.0 ± 32.6 vs. 41.5 ± 11.5 pg./mL, p < 0.0001), than the MCI non-AD group. The gene discussed is MAPT; the disease is Alzheimer disease.