PSEN1 and Alzheimer disease: Although a definitive etiology of AD/ADRD is yet unknown, both genetic factors, such as Amyloid-beta precursor protein (APP), Presenilin-1 (PS1), Presenilin-2 (PS2) genes, and environmental factors (e.g., volatile anesthetics, toxic metals, industrial chemicals, air pollutants, and pesticides) are believed to be involved [2].