Activity of β- or γ-secretase did not significantly correlate with the post-mortem delay (r = −0.177, p = 0.10 and r = −0.101, p = 0.36, respectively) or with the age of death (r = 0.142, p = 0.20 and r = 0.096, p = 0.38, respectively) in the AD cohort. This evidence concerns the gene PPIB and Alzheimer disease.