No association between D-2 dopamine receptor (DRD2) "A" system alleles, orDRD2 haplotypes, and posttraumatic stress disorder

Background: Association studies between marker alleles at the D-2 dopamine receptor gene (DRD2) and various psychiatric illnesses have produced confli cting results. Reports of allelic associations were originally made with al coholism, bur were then extended to other psychiatric disorders, including posttraumatic stress disorder (PTSD). Methods: We studied allele frequency of the DRD2 TaqI "A," "B," and "D" sys tem markers in 52 European-American subjects with diagnoses of PTSD (based on structured interviews). Results: Frequency of the AI allele in this sample was .15, not significant ly different from the .19 allele frequency seen in 87 control subjects. We were thus unable to replicate the previous reports of allelic association b etween the DRD2 TaqI "A1" allele and PTSD. There were also no significant d ifferences in allele frequency for the "B" or "D" systems. We then computed three marker (TaqI "A," "B," and "D" system) haplotypes for the sample; DR D2 haplotype frequencies also did not differ between control subjects and s ubjects with PTSD, Conclusions: We conclude that DRD2 alleles are not associated with PTSD in this sample, and that genetic variation at the DRD2 locus is not likely to be an important contributor to risk for this disorder, Biol Psychiatry 1999 ;45:620-625 (C) 1999 Society of Biological Psychiatry.