Investigation of dopamine system genes in obsessive-compulsive disorder

Authors:
  • MRM. A. Richter
    M. A. Richter
  • FSF. Sam
    F. Sam
  • RSR. P. Swinson
    R. P. Swinson
  • XDX.-Y. Dai
    X.-Y. Dai
  • NKN. King
    N. King
  • FBF. Badri
    F. Badri
  • TST. Sasaki
    T. Sasaki
  • JBJ. A. Buchanan
    J. A. Buchanan
  • JKJ. L. Kennedy
    J. L. Kennedy
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Abstract
Evidence from anatomical, pharmacological, and animal studies on the involvement of the dopamine system in obsessive-compulsive disorder (OCD) is mounting. This, along with evidence for a genetic diathesis provided by family and twin studies, prompted us to conduct genetic association studies of dopamine system genes in OCD. We genotyped OCD patients (n > 100) and matched controls for four loci: (1) a 40-base-pair repeat in the dopamine transporter gene; (2) the Taq1A polymorphism and the serine/cysteine variation in the D2 dopamine receptor gene; (3) an MscI polymorphism in the D3 dopamine receptor gene; and (4) a 48-base-pair repeat in the D4 dopamine receptor gene. Significant differences in allele frequencies were found between patients and controls for the D4 receptor gene, although replication is required with family-based controls before any conclusions can be entertained. This study represents the first comprehensive assessment of the roles of dopamine system genes in OCD.