FAD is often caused by inherited mutations in the genes encoding for amyloid precursor protein (APP) and presenilin 1 (PSEN1), and the cognitive and pathological symptoms observed strongly resemble those seen in late-onset AD (LOAD), the more prominent form of AD (Duara et al., 1993; Lippa et al., 1996; Day et al., 2016). The gene discussed is PSEN1; the disease is Alzheimer disease.