rs2134655

This candidate gene study identified four SNPs in the DRD3 (dopamine D3 receptor) gene associated with reduced risk for posttraumatic stress disorder (PTSD) in a discovery sample of 491 white non-Hispanic trauma-exposed veterans and partners (rs2134655, rs201252087, rs4646996, and rs9868039; odds ratios 0.59-0.69; corrected p-values 0.005-0.049). In a replication sample of 601 trauma-exposed African Americans, rs2251177, located 149 bp from the top discovery SNP, showed nominal association with PTSD in men (OR=0.32, uncorrected p=0.01). The protective alleles suggest DRD3 dysfunction may mediate PTSD through effects on executive functioning and emotional reactivity.

Association study of 55 SNPs in 887 Hungarian adults examining genetic predisposition to aggression measured by the Buss-Perry Aggression Questionnaire. The HTR2A rs7322347 intronic variant showed significant association with aggression after Bonferroni correction (p = 0.0007), with carriers of the minor A allele showing lower aggression levels. The DRD4 rs916455 variant also showed nominal significance (p = 0.0275) but did not survive multiple testing correction.

A pharmacogenetic study of 446 schizophrenic patients (221 males, 225 females) from West Siberia investigating associations between 41 SNPs in dopaminergic genes and antipsychotic-induced hyperprolactinemia. The study found rs1799836 in MAOB gene associated with hyperprolactinemia in males (OR=0.748, p=0.048), and rs40184 and rs3863145 in SLC6A3 gene associated with hyperprolactinemia in the risperidone/paliperidone subgroup (OR=0.341, p=0.021 and OR=0.362, p=0.043, respectively), indicating protective effects.

This systematic review of 98 studies examined biological predictors of clozapine response in treatment-resistant schizophrenia patients. Of 379 different gene variants investigated across 70 genetic studies, only three variants (DRD3 Ser9Gly rs6280, HTR2A His452Tyr, and GNB3 C825T) achieved independent replication. Non-genetic predictors included higher prefrontal cortical volumes and lower HVA:5-HIAA ratio in cerebrospinal fluid.

This meta-analysis of 794 schizophrenia cases and 1,078 controls from three European populations identified a common protective DRD3 haplotype against schizophrenia (Mantel-Haenszel χ² p-value = 0.00227; OR = 0.79, 95% CI 0.68-0.92). The protective haplotype has reached high frequency in non-African populations through positive selection acting on the non-synonymous SNP rs6280 (Ser9Gly), suggesting natural selection influences susceptibility allele frequencies in psychiatric disorders.

A systematic review of 98 studies investigating biological predictors of clozapine response in treatment-resistant schizophrenia. Of 70 genetic studies examining 379 variants, only three genetic variants have independently replicated findings: DRD3 Ser9Gly (rs6280), HTR2A His452Tyr, and GNB3 C825T (rs5442/rs5443). Non-genetic predictors include higher prefrontal cortical structural integrity and activity, and lower HVA:5-HIAA ratio in cerebrospinal fluid.

Haplotype-tagging SNP analysis in 364 individuals from 152 ADHD families identified significant associations between commission errors and SNPs in the DRD2 gene (rs2075654, rs1079596) and between reaction time variability and a SNP in the NET gene (rs3785155). These findings suggest that commission errors and reaction time variability are valid ADHD endophenotypes linked to dopaminergic and noradrenergic pathways.

A pharmacogenetic association study of 446 schizophrenia patients from West Siberia examined 41 SNPs in dopamine pathway genes (DRD1, DRD2, DRD3, DRD4, SLC6A3, MAOA, MAOB) for association with antipsychotic-induced hyperprolactinemia (HPRL). rs1799836 in MAOB showed significant protective association with HPRL in men (OR=0.748, p=0.048), while rs40184 (OR=0.341, p=0.021) and rs3863145 (OR=0.362, p=0.043) in SLC6A3 showed protective effects specifically in risperidone/paliperidone-treated patients.