It's important to note that while Amyloid Precursor Protein (APP) itself is not a biomarker, the cleaved fragments, especially Aβ (1−40) and Aβ (1−42), are widely used as biomarkers to detect and characterize AD.Additionally, the Aβ1–40/Aβ1–42 ratio serves as another valuable biomarker in AD, offering insights into the amyloid burden in the brain and aiding in the diagnostic process. This evidence concerns the gene APP and Alzheimer disease.