Additionally, genetic factors, including mutations in APP, presenilin 1 (PSEN1), and presenilin 2 (PSEN2), as well as the ε4 allele of apolipoprotein E (APOE4), increase the risk of AD by influencing amyloid and tau pathology (Karran and De Strooper 2016). This evidence concerns the gene PSEN1 and Alzheimer disease.