PSEN2 and Alzheimer disease: In 2011, as AD studies in patients who had non-familial cases of early sporadic AD were ongoing, the Dominantly Inherited Alzheimer Network Trials Unit (DIAN-TU) collaboration was established to test early-stage interventions in patients with dominantly inherited AD (DIAD) caused by mutations in the APP, PSEN1, or PSEN2 genes [43].