No significant Aβ positive staining signals were detected in 3-, 6-, or 9-month-old WT mice and the 3-month-old AD model group (APP/PS1); however, a large amount of Aβ pathological deposition was found in the brain parenchyma of 6- and 9-month-old AD model mice (Figure 2B). The gene discussed is PSEN1; the disease is Alzheimer disease.