BIOLOGICAL PSYCHIATRY, cilt.56, sa.9, ss.691-697, 2004 (SCI-Expanded)
Background: Several polymorphisms have been identified in the 5' flanking region of the human dopamine receptor gene(DRD4), including a tandem duplication polymorphism. This comprises a 120-base-pair repeat sequence that is known to have different allele frequencies in various populations around the world. Furthermore, various studies have revealed evidence of linkage to attention deficit/hyperactivity disorder disorder and association with schizophrenia and methamphetamine abuse. The location of the polymorphism in the 5' regulatory region of the DRD4 gene and the fact that it consists of potential transcription factor binding sites suggest that it might confer differential transcriptional activity of the alleles.