Association study of four dopamine D1 receptor gene polymorphisms and clozapine treatment response

Rudi Hwang, Takahiro Shinkai, Vincenzo De Luca, Xingqun Ni, Steven G. Potkin, Jeffrey A. Lieberman, Herbert Y. Meltzer, James L. Kennedy*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

41 Scopus citations


Dopamine D1 receptors (D1) in the prefrontal cortex have been implicated in the modulation of cognitive processes as well as both positive and negative symptoms of schizophrenia. Therefore pharmacologic agents with potent D1 effects such as clozapine may influence the symptoms of schizophrenia (SCZ). Genetic variation in the D1 receptor gene (DRD1) may help to explain some of the variability in patient response to antipsychotics (APs). This study investigates the effect of four single nucleotide polymorphisms (SNPs) in DRD1 on clozapine response in two distinct SCZ populations (Caucasian and African American) refractory or intolerant to conventional APs. This study included 183 Caucasian and 49 African American schizophrenics diagnosed using the Diagnostic and Statistical Manual of Mental Disorders (revised third or fourth edition). Genotyping was determined by 5'-exonuclease fluorescence assays. Within each population genotype, allele, allele +/- and haplotype frequencies were compared against dichotomous and quantitative measures of treatment response. Linkage disequilibrium analysis was also performed. In the Caucasian sample, no associations were observed for individual SNP tests. However, a rare three-marker haplotype predicted poor response. In the African American sample, the rs265976 variant and another three-marker haplotype were associated with clozapine response. Although we did not find an association between the rs4532 SNP (-48 A/G, recognized by a DdeI restriction cut site) and clozapine response as reported by Potkin et al. (2003), a trend in the same direction was observed as well. Our findings suggest that the rs4532 SNP may have a small effect if any. Further studies in larger, independent samples are required to validate these findings.

Original languageEnglish (US)
Pages (from-to)718-727
Number of pages10
JournalJournal of Psychopharmacology
Issue number7
StatePublished - Sep 2007


  • Antipsychotics
  • Association study
  • Clozapine
  • Dopamine D1
  • Pharmacogenetics
  • Response
  • Schizophrenia

ASJC Scopus subject areas

  • Pharmacology
  • Psychiatry and Mental health
  • Pharmacology (medical)


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