rs6295

A perspective article examining schizophrenia as an oscillopathy rooted in language evolution. The authors argue that schizophrenia-related genes are overrepresented among genes important for human language evolution, with many involved in brain rhythmicity and neural oscillations. They propose that language deficits in schizophrenia arise from disruptions in oscillatory neural dynamics and suggest specific brain rhythm patterns (delta, theta, alpha, beta, gamma) correlate with linguistic impairments.

This case-control study of 59 women with PMDD and 74 controls examined the effect of the HTR1A rs6295 polymorphism on cognitive function across the menstrual cycle. Women with PMDD showed impaired working memory and cognitive control in the premenstrual phase compared to controls. The G/G genotype of HTR1A (rs6295) was significantly associated with poorer working memory (2-back task) in the premenstrual phase and moderated the effect of PMDD on cognitive function, supporting the serotonin dysfunction hypothesis of PMDD.

This molecular imaging genetics study investigated 52 healthy Caucasian volunteers to determine whether the common COMT gene polymorphism rs4680 (VAL158MET) affects serotonin-1A (5-HT1A) receptor binding. Using PET imaging with [carbonyl-11C]WAY-100635, the researchers found that homozygote GG carriers showed significantly higher 5-HT1A receptor binding potential compared to A carriers (AA+AG) in multiple brain regions including the posterior cingulate cortex (F(2,49)=17.7, p=0.05, FWE corrected), orbitofrontal cortex, anterior cingulate cortex, insula, amygdala, and hippocampus. The effect sizes were large (Cohen's d=1.43 for AA vs. GG), supporting the hypothesis that COMT may modulate serotonergic neurotransmission relevant to mood and anxiety disorders.

Meta-analysis of 15 studies (4,297 patients, 5,435 controls) found that the serotonin 1A receptor gene (HTR1A) SNPs rs6295 (C-1019G) and rs878567 are significantly associated with mood disorders and major depressive disorder. The rs6295 G allele was protective against mood disorders (OR = 0.87, 95% CI 0.79-0.96, P = 0.007 in allele model), with stronger effects in Asian populations (OR = 0.81, P = 0.0007). rs878567 also showed protective association with mood disorders (OR = 0.83, P = 0.0002).

Case-control association study investigating 42 SNPs in 10 genes in 221 Korean schizophrenia inpatients and 170 healthy controls. The 5HTR1A variant rs10042486 showed significant association with schizophrenia (χ² = 11.32, p = 0.003) and clinical improvement on PANSS scores; subjects with TT genotype showed greater improvement than CC/CT carriers (F = 178.77, p = 0.002 for PANSS total; p < 0.001 for positive and negative subscales). No significant associations were found for the other 41 SNPs.

This review article examines the link between genes and language deficits in schizophrenia through the lens of neural oscillations and brain rhythmicity. The authors argue that candidate genes for schizophrenia are overrepresented among genes important for human language evolution, and propose that schizophrenia can be understood as an oscillopathy affecting language-relevant brain circuits, particularly those involving GABAergic inhibitory interneurons and oscillatory dynamics in the hippocampus and prefrontal cortex. The paper presents evidence that genes like ZNF804A, NRG1, ERBB4, CACNA1C, and GRIN2A are involved in both brain rhythmicity and schizophrenia susceptibility.

This review chapter synthesizes genetic research on suicidal behavior, covering family, twin, and adoption studies demonstrating ~45% heritability. It highlights key serotonergic genes (TPH1, TPH2, 5-HTT, 5HTR1A, 5HTR2A) associated with suicide risk, dopaminergic pathway genes (DRD2, COMT Val158Met showing increased risk), BDNF (reduced levels in suicide victims), and genome-wide linkage studies identifying suicide risk loci on chromosomes 2p, 5q, 6q, 8p, 11q, and Xq. The review concludes that serotonergic candidates represent the most credible evidence for genetic susceptibility to suicide.

A gene-environment interaction study in 183 personality disorder patients and 123 adult ADHD patients examining serotonergic candidate genes (5-HTT, HTR1A, TPH2) with stressful life events. HTR1A rs6295 G allele increased risk of cluster B personality disorders (OR=1.99, p=0.019) and decreased cluster C risk in ADHD (OR=0.44, p=0.016). 5-HTTLPR and TPH2 rs4570625 showed significant G×E interactions with life events for personality disorder traits.

This Hungarian dissertation examined psychogenetic endophenotypes in healthy young adults (N~1800+), investigating associations between dopaminergic and serotonergic genetic polymorphisms and psychological traits including impulsivity, mood dimensions, flow susceptibility, hypnotizability, and cognitive performance. Key findings included significant associations between DRD4 VNTR 7-repeat allele and lower impulsivity (p=0.006), COMT Val/Met (rs4680) and impulse control (p=0.047), HTR1B 1997 AG (rs13212041) and impulsivity (p=0.003-0.004), GDNF variants and anxiety, and notably, a population frequency increase in DRD4 7-repeat allele carriers with advancing age suggesting possible survival advantage.

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.

A Hungarian doctoral dissertation examining psychogenetic endophenotypes through multiple candidate gene association studies. Investigated dopaminergic and serotonergic polymorphisms (DRD2, DRD4, COMT, GDNF, HTR1A, HTR1B, SLC6A4) in relation to personality dimensions (impulsivity, anxiety, depression), flow susceptibility, hypnotizability, cognitive reaction time, and longevity. Key findings include associations between GDNF rs3812047 and rs3096140 with anxiety measures (p=0.0007, p=0.0014), COMT Val158Met with hypnotizability, and DRD4 VNTR 7-repeat with reaction time.

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.

This imaging genetics study examined the effect of HTR1A C(-1019)G (rs6295) on amygdala reactivity and trait anxiety in 89 healthy adults. The -1019G allele was associated with significantly decreased threat-related amygdala reactivity (right: p=0.030, left: p=0.045), independent of the 5-HTTLPR polymorphism. Path analyses revealed that HTR1A genotype indirectly predicted 9.2% of trait anxiety variability through its effects on amygdala reactivity, with no significant direct genotype effect on trait anxiety.

This review of molecular genetic studies of ADHD in Han Chinese populations summarizes candidate gene studies across dopaminergic, noradrenergic, serotonergic, and enzymatic systems, along with the first GWAS in Chinese ADHD cases (n=1040) and controls (n=963). While no single gene has been definitively identified, significant associations include DRD4 7-repeat allele (OR=1.70, 95% CI 1.20-2.40, p=0.003 in males), DBH rs2519152, and various polymorphisms in COMT, NET1, and serotonin genes, though results remain inconsistent across studies.

This case-control study examined 367 major depressive disorder patients to determine if HTR1A rs6295 (-1019C>G) and DAT1 repeat variants interact to increase borderline personality disorder (BPD) risk. Patients with DAT1 9,10 or 9,9 genotypes had OR=3.27-2.67, while HTR1A G,G homozygotes had OR=2.03. Combined high-risk variants (9,10;G,G and 9,9;G,G) showed dramatically elevated risk (OR=6.64 and OR=5.42, respectively), with up to 9-fold difference between highest and lowest risk groups.

This two-stage case-control association study examined four SNPs spanning the HTR1A gene (serotonin 1A receptor) in 589 cases and 539 controls selected for extreme genetic risk of depression and anxiety disorders. Although rs1364043 showed nominally significant association in stage 1 (P<0.1), this failed to replicate in stage 2, and multi-marker haplotypes including the previously implicated C(-1019)G promoter polymorphism (rs6295) showed no consistent associations. The findings suggest HTR1A genetic variation alone is unlikely to contribute substantially to genetic susceptibility to depressive and anxiety-related phenotypes.

This association study examined epistatic interactions among seven serotonin pathway genes in autism etiology using 186 autistic families and 181 controls. The authors found a significant main effect of HTR5A rs1800883 (P = 0.0088), and identified a significant three-locus epistatic interaction between SLC6A4 intron 2 VNTR and ITGB3 rs5918 with additive HTR5A rs6320 effects (P < 0.001) associated with autism risk. Additionally, ITGB3 haplotypes showed association with platelet serotonin levels (P = 0.0163), supporting a common genetic mechanism linking gene interactions to both autism susceptibility and hyperserotonemia.

This review examines molecular genetic studies of attention-deficit hyperactivity disorder (ADHD) in Han Chinese samples, including candidate gene studies, endophenotype research, genome-wide association studies, and pharmacogenomic investigations. Eight GWAS conducted for ADHD have been inconclusive with no genome-wide significant associations identified, though candidate gene studies have identified associations with dopaminergic (DAT1, DRD4, DRD2, DRD3), noradrenergic (NET1, ADRA2A, ADRA2C), serotonergic (SLC6A4, HTR genes), and metabolic pathway genes (COMT, MAOA, MAOB, DBH, TPH). A meta-analysis of DRD4 longer repeats showed OR=1.70-1.74 in males with ADHD-C subtype.

A case-control study (N=99: 49 patients with major depressive disorder, 50 controls) conducted in Mexican mestizo population analyzing 8 genetic variants in serotonin and dopamine receptors (HTR1A rs6295, HTR2A rs6311/rs6313/rs6314, HTR6 rs1805054, DRD2 rs1801028/rs1800497, DRD3 rs6280) using PCR-RFLP genotyping. The study characterized genotype and allele frequencies in depressed patients versus healthy controls and evaluated associations with antidepressant treatment response using Hamilton Depression Scale.

This case-control association study examined 719 war-trauma survivors from the Balkans to investigate the role of serotonergic gene polymorphisms in PTSD development. A nominal significant association was found between the HTR1A SNP rs6295 and Brief Symptom Inventory scores in lifetime PTSD patients (P=0.018 dominant model), with the minor C allele conveying increased risk. However, no significant associations were found for TPH2 SNPs rs11178997 and rs1386494, and the HTR1A findings did not survive Bonferroni correction.