APP and Alzheimer disease: In several studies including ours, platelet APP ratio between the larger and lower isoforms of AD patients is significantly lower compared to healthy control subjects and correlate with disease severity (Di Luca et al. 1996, 1998, 2000; Borroni et al. 2004; Padovani et al. 2001; Baskin et al. 2000; Rosenberg et al. 1997; Zainaghi et al. 2012; Ehrlich et al. 2013).