Beyond immunotherapy, Aβ-targeting compounds that have been tested or are currently under assessment include drugs interfering with APP processing—i.e., α-secretase activators, β-secretase inhibitors, γ-secretase modulators—and inhibitors of Aβ aggregation (Citron, 2010; Suzuki et al., 2017; Umar and Hoda, 2017), based on the view that an increased amyloid production favors the onset of AD in animal models and humans carrying genetic defects in the three causative genes associated with early-onset AD, i.e., APP, presenilin 1 and 2 (Selkoe, 1991; Hardy and Selkoe, 2002; Kunkle et al., 2019). The gene discussed is PSEN1; the disease is Alzheimer disease.