POPULATION STUDIES OF POLYMORPHISMS AT LOCI OF NEUROPSYCHIATRIC INTEREST (TRYPTOPHAN-HYDROXYLASE (TPH), DOPAMINE TRANSPORTER PROTEIN (SLC6A3), D3 DOPAMINE-RECEPTOR (DRD3), APOLIPOPROTEIN-E (APOE), MU-OPIOID RECEPTOR (OPRM1), AND CILIARY NEUROTROPHIC FACTOR (CNTF))

We determined allele frequencies for polymorphisms at several loci of interest in neuropsychiatry-tryptophan hydroxylase (TPH), dopamine tra nsporter protein (SLC6A3), D3 dopamine receptor (DRD3), apolipoprotein E (APOE), ciliary neurotrophic factor (CNTF), and the mu opioid recep tor (OPRM1)-in samples of individuals from populations in several diff erent parts of the world, Associations with psychiatric illness have b een proposed for specific polymorphisms at TPH (suicide-related behavi ors and impulsivity), DRD3 (schizophrenia and bipolar affective disord er), SLC6A3 (susceptibility to cocaine-induced paranoia and attention deficit disorder), CNTF (psychosis), and OPRM1 (substance dependence). APOE alleles are related to risk of Alzheimer disease. We found signi ficant allele frequency variation among populations at all six loci. T hese results will provide a global framework of normal variation at th ese loci that might have functional significance or otherwise be relat ed to susceptibility to various disorders or behavioral phenomena. Kno wledge of this variation can be important for study design and data in terpretation when individuals from various population groups are resea rch subjects and may eventually help lead to a better understanding of behavioral adaptation. (C) 1998 Academic Press.