Isn’t the effect small but the significance good? If I understood it correctly there’s no amyloid beta gene, but genes for APP an genes for proteases cutting A

Isn’t the effect small but the significance good? If I understood it correctly there’s no amyloid beta gene, but genes for APP an genes for proteases cutting APP. As a layman that leaves a lot of other explanations open, for instance other byproducts of the proteolysis, other breakdown mechanisms for APP, …