MARK2 and early-onset autosomal dominant Alzheimer disease: Different neuropsychiatric disorders are often related to one another in their phenotypic characteristics, which could stem out of common genetic variations, or “shared genetics”, exemplified by the genetic overlap between Alzheimer’s disease and bipolar disorder with respect to the MARK2 and VAC14 genes (44), the genetic overlap between SCZ, bipolar disorder, and intelligence (45), and the shared genetic variants between SCZ and lung cancer (46).