Related Experiment Video
Updated: May 26, 2026

Developing a Rat Model for Bipolar Disorder
Published on: May 2, 2025
Dopamine D4 and D5 receptor gene variant effects on clozapine response in schizophrenia: replication and exploration
Rudi Hwang1, Arun K Tiwari, Clement C Zai
1Neurogenetics Section, Centre for Addiction and Mental Health, Toronto, ON, Canada. rudirudi@gmail.com
Objectives:
This study aimed to: 1) replicate previously reported associations between dopamine D4 receptor gene (DRD4) polymorphisms and antipsychotic (AP) response in a clozapine (CLZ) response sample; and 2) explore possible associations of polymorphisms across dopamine D5 receptor gene (DRD5) as well as other DRD4 regions.
Methods:
DRD4 exon III 48-bp, intron I (G)(n), and 120-bp repeat polymorphisms, and three DRD4 single nucleotide polymorphisms (SNPs); and DRD5 (CA/CT/GT)(n) microsatellite and four DRD5 SNPs were assessed using standard genotyping and statistical procedures.
Results:
We report evidence, which does not survive correction for multiple testing, supporting previous DRD4 findings. Findings of interest include the 120-bp 1-copy allele, intron I (G)(n) 142-bp/140-bp genotype, and exon III 4R allele with CLZ response. All DRD5 tests were negative.
Conclusions:
Overall, these results suggest a possible minor contribution of DRD4 variants, but not DRD5 variants, towards the AP/CLZ response phenotype.
More Related Videos
07:25Identification of Dopamine D1-Alpha Receptor Within Rodent Nucleus Accumbens by an Innovative RNA In Situ Detection Technology
Published on: March 27, 2018
05:14Standardized Data Acquisition for Neuromelanin-Sensitive Magnetic Resonance Imaging of the Substantia Nigra
Published on: September 8, 2021
Related Concept Videos
Antipsychotic Drugs: Typical and Atypical Agents
Psychosis: Pathophysiology of Schizophrenia and Other Psychotic Disorders
Researchers have identified genetic factors that increase susceptibility to schizophrenia, underscoring the intricate interplay between genetics and environment in disease development. At the core of schizophrenia's pathophysiology is excessive dopaminergic neurotransmission within the...
Pharmacogenetic Phenotypes: Alterations in Pharmacokinetics, Drug Targets and Biologic Milieu
Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase
Biological Causes of Schizophrenia
Genetic Factors in Schizophrenia
The genetic basis of schizophrenia is strongly supported by family and twin studies.
Human Genetics
The complex relationship between genetics and psychology is observable through common biological components such...