Association between dopamine D3 receptor gene polymorphisms and schizophrenia in an isolate population

There are several lines of evidence implicating the dopamine D3 receptor in the pathophysiology of schizophrenia. The Ser9Gly polymorphism of the dopamine D3 receptor gene (DRD3) has been the most extensively investigated DRD3 variant in connection with the disease but results have been inconclusive. Recent reports indicate that the Ser9Gly polymorphism is in linkage disequilibrium with other markers, but association studies between DRD3 haplotypes and schizophrenia have had mixed results. Genetic heterogeneity may be one of the causes of contradicting results. In order to clarify the role of DRD3 alterations in the aetiology of disease, we have investigated three D3 genetic variants (Ser9Gly, -205-G/A, -7685-G/C) in a sample of patients with schizophrenia or schizoaffective disorder (N=118) and controls (N=162) recruited from a human isolate from Navarra (Northern Spain) of Basque origin. Although no association was found between the Ser9Gly or the -205-A/G polymorphisms and disease, an excess of allele -7685-C was observed in patients (p=0.002 after correction for multiple analyses). Haplotype analysis shows the three markers to be in strong linkage disequilibrium (p<0.0001) and strongly associated with disease (p<1x 10(-5)). These results may suggest that these polymorphisms exert a combined or synergistic effect on susceptibility to schizophrenia, or are in linkage with an unknown causative factor. However, further replication in independent samples is required.     

Association study of RELN polymorphisms with schizophrenia in Han Chinese population

Schizophrenia (SZ) is a common and complex psychiatric disorder with a strong genetic component. Previous research suggests that mutations altering genes in neurodevelopmental pathways contribute to SZ. Reelin gene (RELN) maps to chromosome 7q22.1, the encoded protein plays a pivotal role in guiding neuronal migration, lamination and connection during embryonic brain development. Several reports had indicated that reduced RELN expression is associated with human mental illnesses such as SZ, mood disorders and autism. In this study, case-control association analyses were performed in the Han Chinese population to determine if the RELN gene is a susceptibility gene for SZ. Thirty-seven single nucleotide polymorphisms (SNPs) were genotyped in 528 paranoid SZ patients and 528 control subjects. A significant association was found between rs12705169 and SZ (p = 0.001). Moreover, the haplotypes constructed from five SNPs showed significant differences between cases and controls (p = 0.041). When subjects were divided by gender, rs12705169 remained significant difference only in females (OR = 0.24, 95%CI = 0.14-0.40 for CC and OR = 0.40, 95%CI = 0.27-0.58 for AC), both in the allele and genotype (p = 0.0001 for both). This study describes a positive association between RELN and SZ in the Han Chinese population, and provides genetic evidence to support the gender difference of SZ.     

Association of dopamine receptor polymorphisms with schizophrenia and antipsychotic response in a South Indian population

Background  

Alterations in the dopamine transmission and receptor density are hypothesized in the pathophysiology of schizophrenia but ethnic disparities are reported to exist in disease association and therapeutic response to psychotropic medication. Antipsychotics have higher binding affinity to D2 subtype of dopamine receptor. DRD2 Cys311, TaqIB1 and TaqIA1 variants are considered to have either reduced affinity for dopamine and hypo-dopaminergic activity.     

Association between the SLC6A12 gene and negative symptoms of schizophrenia in a Korean population

We investigated the association of single nucleotide polymorphisms of solute carrier family 6 member 11 (SLC6A11) (rs2304725, rs2272400, and rs2245532), SLC6A12 (rs216250 and rs557881) and SLC6A13 (rs2289954) with schizophrenia and its clinical symptoms. We found that rs216250 of SLC6A12 was correlated with the Scale for the Assessment of Negative Symptoms (SANS) scores.     

Family association study between DRD2 and DRD3 gene polymorphisms and schizophrenia in a Portuguese population

Schizophrenia is a highly heritable condition, as demonstrated in family, twin and adoption studies. Candidate genes from the dopaminergic system have long been hypothesized to be involved in the etiology of this disorder. In the present study, we investigated the genetic association between polymorphisms in the D2 and D3 dopamine receptor (DRD2, DRD3) genes and schizophrenia. We examined 90 trios from Portugal, and negative results were obtained from association studies with both Haplotype Relative Risk (HRR) and Transmission Disequilibrium Test (TDT), as well as TRANSMIT. Therefore, we conclude that neither the DRD2 nor the DRD3 gene polymorphisms investigated are associated with schizophrenia in our sample.     

Association between chromogranin b gene polymorphisms and schizophrenia in the Japanese population.

BACKGROUND: We found in previous work a significant association between schizophrenia and D20S95 on chromosome 20p12.3. In this study, we analyzed 10 microsatellite markers and found an association of schizophrenia with D20S882 and D20S905 that flank D20S95. The chromogranin B gene (CHGB) is 30 kb from D20S905. The chromogranin B (secretogranin I) belongs to a series of acidic secretory proteins that are widely expressed in endocrine and neuronal cells, and its cerebrospinal fluid levels have been reported to decrease in patients with chronic schizophrenia. METHODS: We screened for polymorphisms in CHGB with polymerase chain reaction direct sequencing methods in 24 Japanese schizophrenic patients and identified a total of 22 polymorphisms. Allelic and genotypic distributions of detected polymorphisms were compared between unrelated Japanese schizophrenic patients (n = 192) and healthy control subjects (n = 192). RESULTS: Statistically significant differences in the allelic distributions were found between schizophrenic patients and control subjects for 1058C/G (A353G) (corrected p = 7.7 x 10(-5)) and 1104A/G (E368E) (corrected p = 8.1 x 10(-6)). The 1058C/G and 1104A/G alleles were in almost complete linkage disequilibrium and were in linkage disequilibrium with D20S95. CONCLUSIONS: Results suggest that the CHGB variations are involved in the susceptibility to schizophrenia in our study population.     

Association study of three polymorphisms in the dopamine D2 receptor gene and schizophrenia in the Russian population

Polymorphisms in the dopamine D2 receptor gene (DRD2) have repeatedly been associated with schizophrenia. Recently, the C957T polymorphism (rs6277), which alters mRNA stability and dopamine-induced upregulation of DRD2 expression in cell cultures and DRD2 mRNA translation in vitro, was tested for an association with the disease. Frequency of the C allele, corresponding to a normal wild-type level of expression, was higher in patients compared to controls, and that of the T allele was lower. To replicate and extend previous findings, we conducted an association study of the C957T polymorphism and two additional SNPs (C939T and TaqIA) in 311 patients with a DSM-IV diagnosis of schizophrenia and 364 mentally healthy people from the Russian population as controls. The results of our study confirmed the association between the C957T polymorphism and schizophrenia. Consistent with previous findings, frequency of the C allele and the CC genotype were higher in patients compared to the control group (p = 0.002). Meta-analysis of total 5 samples also suggests significant allelic association. The distribution of C939T genotypes in the case sample was significantly different from that of the controls: in the case sample, the TT genotype frequency was higher compared to the combined frequency of CT and CC genotypes (p = 0.002). Though no association was found between the TaqIA polymorphism and schizophrenia, a haplotype-wise analysis revealed a lower frequency of the T–C (C957T–TaqIA) haplotype in patients (p = 0.02). In conclusion, our findings provide additional evidence for an association between the C957T polymorphism and schizophrenia.     

Association of thromboxane A2 receptor gene polymorphisms with cerebral infarction in a Chinese population

Platelet aggregation is crucial for the development of cerebral infarction (CI) and it is markedly increased due to the binding of thromboxane A2 (TXA2) to its receptor (TXA2R). Therefore, TXA2R plays a central role in the pathogenesis of atherosclerosis and thrombosis. This study aimed to investigate the relationship between human TXA2R gene single nucleotide polymorphisms (SNPs) and non-cardiogenic CI in a Chinese cohort. Two SNPs, rs768963 and rs4523, located in the regulatory and coding regions of TXA2R gene, respectively, were examined in DNA samples from 407 Chinese patients with CI and 270 controls. 407 CI was categorized into subtypes using Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification. There was no significant association between rs4523 variants and CI. However, there was a significant difference in the overall distribution of genotypes and dominant/recessive models of rs768963 between CI and control groups. In addition, multiple logistic regression analysis revealed that the C allele of rs768963 was significantly associated with total CI (P = 0.023), large artery atherosclerosis subtype (P = 0.009), small artery occlusion subtype (P = 0.044) after adjusting for confounding factors (odds ratio = 1.533, 1.918 and 1.573, respectively). we conclude that TXA2R rs768963 polymorphism is associated with CI in a Chinese population.     

Association of calcineurin A gamma subunit (PPP3CC) and early growth response 3 (EGR3) gene polymorphisms with susceptibility to schizophrenia in a Japanese population

To examine the association of PPP3CC (rs10108011 and rs2461491) and EGR3 (rs3750192) single-nucleotide polymorphisms (SNPs) with Japanese schizophrenia, we performed a case–control association study using 337 patients and 369 healthy controls. As a result, by our moderated cohort-size study, PPP3CC and EGR3 are not genetic risk factors for schizophrenia, whereas meta-analysis showed weak association of rs10108011 with schizophrenia in the Japanese population (odds ratio (OR) = 1.12, P = 0.01).     

精神分裂症和2型糖尿病与胞浆型磷脂酶A2基因和断裂基因1的关联分析

目的 探讨精神分裂症与2型糖尿病间是否存在遗传相关性.方法 纳入首发精神分裂症患者133例、正常一级亲属79名、2型糖尿病患者125例和正常对照88名,采用限制性片段长度多态性技术(PCR-RFLP)检测胞浆型磷脂酶A2(cPLA2)基因BanI多态性与断裂基因1(DISCl)rs821616多态性.比较上述4组间BanI与rs821616基因多态分布频率的差异.结果 ①精神分裂症组和2型糖尿病组BanI多态性的A2/A2基因型频率与正常对照组间的差异均有统计学意义(P=0.047,OR=2.419;P=0.043,OR=2.472),A2/A2基因型频率分别为精神分裂症组(17.29%)、一级亲属(13.93%)、2型糖尿病(17.60%)、对照组(7.96%);A1/A2、A1/A1基因型和A1、A2等位基因频率组间比较差异均无统计学意义(P＞0.05);②4组间rs821616多态性的基因型和等位基因分布频率差异均无统计学意义(P＞0.05).结论 cPLA2基因BanI多态性与精神分裂症和2型糖尿病均可能存在关联,提示cPLA2基因可能与两种疾病均相关;未发现rs821616多态性与精神分裂症或2型糖尿病关联.     

CTLA-4 single-nucleotide polymorphisms in a Caucasian population with schizophrenia

Associations between a single-nucleotide polymorphism (SNP) in exon 1 of the cytotoxic T-lymphocyte antigen-4 (CTLA4) gene and schizophrenia in a Korean population have been previously described. The current study investigated whether a similar link occurs in a Caucasian population with schizophrenia. One hundred and twenty-two age- and sex-matched pairs of people with DSM-III-R diagnosis of schizophrenia and healthy controls were included in this study. Three previously described SNPs (from the promoter, exon 1 and 3' UTR) of the CTLA4 gene were analysed. In the entire sample, we detected no allelic or genotypic association for any of the three SNPs. Given documented gender differences in incidence of schizophrenia, we conducted separate analyses of male and female participants. In males, both the promoter region SNP (-318C/T) and the 3' UTR SNP demonstrated nominally significant association with schizophrenia. The 3' UTR SNP remained significant following correction for multiple testing (permuted P=0.046). In addition, all possible haplogenotypes showed significant association with disease in males with two--both containing the 3' UTR SNP--remaining significant following correction for the genotypic tests of all SNPs and haplogenotypes in males. These results suggest a role for the 3' UTR SNP and/or variants in high linkage disequilibrium with this SNP in the pathogenesis of schizophrenia.     

Association between polymorphisms of arachidonate 12-lipoxygenase (<Emphasis Type="Italic">ALOX12</Emphasis>) and schizophrenia in a Korean population

Arachidonic acid (AA), an essential polyunsaturated fatty acid, is one of the major components of neural membranes, which show an altered phospholipid composition in schizophrenia. Arachidonate 12-lipoxygenase (ALOX12), an important enzyme, metabolizes AA to 12-HPETE, which affects catecholamine synthesis. However, research has yet to show the genetic association between ALOX12 and schizophrenia. Therefore, we investigated single nucleotide polymorphisms (SNP) of the ALOX12 gene in schizophrenia, recruiting patients with schizophrenia (n = 289) and normal controls (n = 306) from a Korean population. We selected three SNPs (rs1126667, rs434473, and rs1042357) of the ALOX12 gene and genotyped them by direct sequencing. We reviewed the schizophrenic patients' medical records and assessed them clinically using the Brief Psychiatric Rating Scale (BPRS), the Scale for the Assessment of Negative Symptoms (SANS), and the Operational Criteria Checklist (OPCRIT). Then we statistically analyzed the genetic associations between the SNPs and schizophrenia, finding a genetic association between both rs1126667 and rs1042357 and schizophrenia, in the recessive model (p = 0.015 and 0.015, respectively). We also found an association between rs434473 and negative symptoms, defined through a factor analysis of the OPCRIT data (p = 0.040). Consequently, we suggest that SNPs of the ALOX12 gene might be associated with schizophrenia and negative symptoms in this Korean population. These weak positives require additional study.     

Association analysis of G72/G30 polymorphisms with schizophrenia in the Korean population

Several studies examining the association between G72/G30 polymorphisms and schizophrenia in cohorts of various ethnic origins have recently been reported. The aim of the current study was to examine the genetic influence of the G72/G30 polymorphisms in the Korean population. Nine G72/G30 single-nucleotide polymorphisms (SNPs) were genotyped in 388 patients with schizophrenia and 367 normal controls from the Korean population. Based on statistical analyses, the positive associations of previous studies of other populations were not replicated in the present study. However, 2 of the 9 tested SNPs, rs778294 and rs947267, were found to be associated with the risk of schizophrenia after correction for multiple testing (P(cor)=0.03 and P(cor)=0.04, respectively). The rs778294 SNP, taken singly, had not been found to be associated with schizophrenia in previous studies, and the second SNP, rs947267, showed an opposite direction of genetic effect on schizophrenia risk here than in a previous study. Our association results were not consistent with those found in other populations, and, thus could be chance findings. Therefore, further studies with larger sample sizes are needed to confirm a risk allele for this gene if it exists.     

汉族人群NTRK2基因多态性与精神分裂症关联研究

目的在中国汉族人群中探讨神经营养性酪氨酸激酶2型受体(NTRK2)基因rs1187272多态性与精神分裂症的关联性。方法采用TAQMAN探针SNP基因分型技术在中国汉族人群中对100例精神分裂症患者及119例正常对照者进行NTRK2基因rs1187272的分型,并进行等位基因及基因型比较。结果患者组与正常对照组之间,NTRK2基因rs1187272多态的等位基因分布(χ2=1.78,df=1,P>0.05)和基因型分布(χ2=1.01,df=2,P>0.05)无明显差异;男、女患者与正常对照组之间,等位基因分布(χ2=2.70,df=3,P>0.05)和基因型分布(χ2=4.72,df=6,P>0.05)也无明显差异;但在不同发病年龄组之间,NTRK2基因rs1187272多态性等位基因分布(χ2=5.53,df=1,P=0.02)存在显著差异,在早发病患者组与对照组之间比较,NTRK2基因rs1187272多态性等位基因分布存在显著差异(χ2=4.38,df=1,P=0.04)。结论在中国汉族人群中NTRK2基因rs1187272多态性与早发精神分裂症(发病年龄≤25岁)存在关联,其可能是早发精神分裂症的易...     

Association between dementia and vascular disease-associated polymorphisms in a Tunisian population

Purpose: Dementia is a multifactorial idiopathic pathology caused by clinical, eDementia is a multifactorial idiopathic pathology caused by clinical, environmental and genetic factors. Hence, its etiology is still unknown. We aimed to evaluate the association between five genetic risk factors for vascular diseases and dementia individually and when gathered in haplotypes. Materials and Method: We enrolled 200 dementia patients and 300 controls. All subjects were genotyped for vascular diseaseassociated polymorphisms in the genes coding for Apolipoprotein-E (ApoE), angiotensin converting enzyme (ACE) and Paraoxonase-1 (PON1). Results: The association between dementia risk and all the studied polymorphisms except of PON1-Q192R was found to be significant. Carrying the ApoE e4 allele seems to increase dementia risk by 4.32 fold (p = 0.001). The risk associated with ACE I and PON1-L55M T alleles were lower (2.58 and 2.11 fold, p < 0.001 and p = 0.015, respectively). When combined in haplotypes, these polymorphisms showed a cumulative and synergetic effect. GTICC haplotype appears to be associated with 9-fold dementia risk (p < 0.001), whereas AADTT seems to reduce dementia risk by 80% (p = 0.003). Conclusion: Our results suggest that, ApoE ε4, ACE I and PON1-L55M T alleles are associated with dementia risk whether these polymorphisms were studied separately or gathered in haplotypes. Still, the contribution of each gene to the pathophysiological development of dementia must be more investigated.     

Association study of polymorphisms in glycine transporter with schizophrenia

Summary. Glycine acts as an obligatory co-agonist with glutamate on N-methyl-D-aspartate (NMDA) receptors. Brain glycine availability is determined by glycine transporters (GlyT1 or SLC6A9), which mediate glycine reuptake into nerve terminals. Since hypofunction of NMDA receptors has been implicated in the pathophysiology of schizophrenia, this study tests the hypothesis that GlyT1 genetic variants confer susceptibility to schizophrenia. Four GlyT1 polymorphisms were studied in a sample population of 249 people with schizophrenia and 210 normal controls. One polymorphism (rs16831541) was not informative in our Chinese population while the other three polymorphisms (rs1766967, rs2248632 and rs2248253) were analysed with chi-square tests and haplotype analysis. Significant linkage disequilibrium was obtained among the three polymorphisms. Neither single marker nor haplotype analysis revealed an association between variants at the GlyT1 locus and schizophrenia, suggesting that it is unlikely that the GlyT1 polymorphisms investigated play a substantial role in conferring susceptibility to schizophrenia in the Chinese population. Further studies with other GlyT1 variants, relating either to schizophrenia, psychotic symptoms or to therapeutic response in schizophrenia, are suggested.     

中国汉族人群磷酸酶与张力蛋白同源物基因多态性与早发性精神分裂症的关联研究

目的：探讨中国汉族人群磷酸酶与张力蛋白同源物（phosphataseandtensinhomolog,PTEN）基因多态性与早发性精神分裂症（EOS）的关系。方法：纳入270例EOS患者和447名健康对照,用SNaPshot技术对PTEN的标签SNP进行基因分型,比较其等位基因、基因型、单体型分布频率在两组间有无差异。结果：rs2299941的等位基因分布在两组间存在边缘统计学差异（X2=4．454,P：0．035,校正P=0．175）,GG基因型在隐性遗传模式下显著降低EOS的发生风险（OR=0．51,95％CI=0．31～0．85,P=0．007）。rs17562384的CC基因型在隐性遗传模式下显著增加EOS的发生风险（OR：2．23,95％CI=1．01～4．91,P=0．047）。单体型GTr（rs2299941、rsl7562384、rs532678）的分布频率在患者组与对照组间存在边缘统计学差异（O．308VS0．364;x2=4．677,P=0．031,校正P=0．057）。结论：中国汉族人群PTEN基因多态性与EOS易感性有关。