In the normal physiological state, APP is cleaved through the non-amyloidosis pathway, in which APP is firstly cleaved by α secretory enzyme, producing a segment called sAβPPα; then, the fragments undergo β and γ secretase cleavage to form non-toxic fragments of P3, Aβ16 and Aβ17–40/42, respectively. This evidence concerns the gene APP and amyloidosis.