APP and Alzheimer disease: Presenilin 2 (Psen2), which cleaves proteins such as APP (amyloid-beta precursor protein) (De Strooper et al. 2012) and has been shown to cause Alzheimer’s disease, displays a change in ASE (Fisher’s exact; q = 0.00001) and a 2.7-fold decrease in RNA transcript levels (Fig. 9c).