Schizophrenia genetic research has traditionally focused on identifying linkage regions or on candidate genes and polymorphisms, such as the val158met polymorphism in the dopamine metabolizing gene COMT, or other types of variants such as VNTRs (MAOA, DAT1, SLC6A4). Such studies have implicated dozens of genes and variants, but none is generally accepted as definitively associated with schizophrenia [13]–[15].
