APP and Alzheimer disease: In the elderly human brain, Aβ deposition is more related to faulty Aβ clearance mechanisms (ca. 5%/h clearance for AD patients vs. ca. 8%/h clearance for control subjects, p < 0.03) than to overproduction of Aβ protein (ca. 7%/h of Aβ production for control subjects and AD patients) [14, 46, 47], although different forms of APP and Aβ overproduction can be the primary cause of Aβ accumulation in certain genetic forms of AD [48].