The levels of the following have previously been found to be different between control and AD subjects: alpha-1-antitrypsin [9], [24], APOE [9], cortisol [9], [25], [26], interleukin-3 [27], matrix metalloproteinase-9 [9], [28], pancreatic polypeptide [9], [29], serum amyloid p-component [30] and von Willebrand factor [31]. This evidence concerns the gene PPY and Alzheimer disease.