Then, two-way analysis of covariance (ANCOVA) was applied to investigate main effects and interactions of PD and DRD3 Ser9Gly polymorphism on the brain function via amplitude of low-frequency fluctuations (ALFF) approach.
Remarkably, alleles of <i>COMT</i> rs165774 (G), <i>DRD2</i> rs6277 (T), and <i>DRD3</i> rs6280 (C) were associated with raised predisposition to schizophrenia (all <i>P</i><0.001).
To assess the relationship between cognitive function, a proposed schizophrenia endophenotype, and two genetic polymorphisms related to dopamine function, catechol-O-methyl transferase (COMT) Val158Met and dopamine receptor 3 (DRD3) Ser9Gly.
In this sample, we found a possible interaction between the BDNF Val66Met and DRD3 Ser9Gly SNPs in increasing the risk of suicide attempt(s) in our SCZ sample.
The meta-analysis comprising 1291 East Asian subjects also showed no association between the polymorphism and TD; the Mantel-Haenszel pooled OR for TD among carriers of the DRD3 Ser9Gly of the eight Asian studies was 0.94 (95% CI: 0.78-1.12).
In our Japanese case-control sample (43 with TD/157 without TD), we found no association between the DRD3 Ser9Gly polymorphism in schizophrenia and TD (genotype: p=0.92; allele: p=1.00).
The meta-analysis comprising 1291 East Asian subjects also showed no association between the polymorphism and TD; the Mantel-Haenszel pooled OR for TD among carriers of the DRD3 Ser9Gly of the eight Asian studies was 0.94 (95% CI: 0.78-1.12).
The presence of diphasic dyskinesia (DDSK) was exclusively associated with the DRD3 p.S9G variant after adjusting for gender, age at PD onset, Hoehn & Yahr stage, and duration of levodopa treatment.
Among white Hispanics who carried two alleles, the Ser9Gly DRD3 (rs6280) polymorphism was associated with a decreased risk of PD (OR=0.4, 95% CI 0.2-0.8).
Consequently, we observed that the genotypic distribution of rs6280 was nominally associated with SZ (P = 0.045), with the ancestral CC genotype being significantly over-represented in SZ patients.
Based on allele and genotype frequencies in both groups, we found no significant association of DRD3 Ser9Gly polymorphisms and COMT (rs165656) with schizophrenia in Malays.
We did not identify any effect of DRD3 Ser9Gly on tremor in PD, even when regarding various symptom combinations to avoid missing a weak effect on the phenotype.
Thus, a number of studies have focused on the association of dopamine system gene polymorphisms and TD, with the most consistent findings being an association between TD and the Ser9Gly polymorphism of the DRD3 gene and the TaqIA site 3' of the DRD2 gene.
As recent observations indicate the dopamine D(3) receptor (DRD3) to modulate both therapeutic action of levodopa and dyskinesia, we reappraised the impact of the DRD3 Ser9Gly polymorphism on development of motor complications in a large scale association study based on the gene bank of the German Competence Network on Parkinson's disease.
We investigated whether the efficacy of aripiprazole can be predicted by a functional DRD3 gene polymorphism Ser9Gly (rs6280) as modified by clinical factors in Han Chinese hospitalized patients with acutely exacerbated schizophrenia.