Moreover, besides neurotransmitters, platelets contain proteins such as APP and produce beta-amyloid and secretases, making them an interesting target to study peripheral changes in AD as they may be useful biomarkers of the disease (Rainesalo et al. 2005; Chen et al. 1995; Li et al. 1999; Evin et al. 2003). This evidence concerns the gene APP and Alzheimer disease.