Chinese Case-control Sample Research Articles

Association analysis of the GRM8 gene with schizophrenia in the Uygur Chinese population.

GRM8 is a schizophrenia candidate gene that is also thought to be involved in the glutamate pathway, which is very important in the pathogenesis of schizophrenia. In this study, we aim to investigate the association between GRM8 and schizophrenia in the Uygur Chinese population. Rs2237748 and rs2299472, located in the GRM8 gene, were selected for genotyping in a set of Uygur Chinese case-control samples, which included 723 cases and 561 controls, using TaqMan assays and capillary sequencing. The statistical analysis was carried out using the online software program SHEsis, and a meta-analysis was carried out to identify other relevant studies using Review Manager 5. We found that the rs2299472 genotype was significantly associated with schizophrenia (P = 0.015, P = 0.030, after Bonferroni correction). The frequency of the CC genotype was higher in the schizophrenic patients (P = 0.008), and the frequency of the AC genotype was lower (P = 0.008). Furthermore, the meta-analysis incorporating the previous and current studies also showed that rs2299472 is associated with schizophrenia. This study indicates that the GRM8 gene may play an important role in the pathogenesis of schizophrenia.

Association Between Single Nucleotide Polymorphisms in miRNA196a-2 and miRNA146a and Susceptibility to Hepatocellular Carcinoma in a Chinese Population

Hepatocellular carcinoma (HCC) is one of the most prevalent cancers in the world and deeply threatens people's health, especially in China. Techniques of early diagnosis, prevention and prediction are still being discovered, among which the approaches based on single nucleotide polymorphisms in microRNA genes (miRNA SNPs) are newly proposed and show prospective potential. In particular, the association between SNPs in miRNA196a-2 (rs11614913) and miRNA146a (rs2910164) and HCC has been investigated. However, the conclusions made were conflicting, possibly due to insufficient sample size or population stratification. Further confirmations in well-designed large samples are still required. In this study, we verified the association between these two SNPs and the susceptibility to HCC by MassARRAY assay in a 2,000 large Chinese case-control sample. Significant association between rs11614913 and HCC was confirmed. Subjects with the genotype of CT+TT or T allele in rs11614913 were more resistant to HCC (CT+TT: OR (95% CI)=0.73 (0.57-0.92), P=0.01; T allele: OR (95% CI)=0.85 (0.75-0.97), P=0.02) and HBV-related HCC (CT+TT: OR (95% CI)=0.69 (0.53-0.90), P=0.01; T allele: OR (95% CI)=0.82 (0.71-0.95), P=0.01). The affected carriers of CT or TT also tended to have lower levels of serum AFP (P=0.01). This study demonstrated a role of rs11614913 in the etiology of HCC. Further research should focus on the clinical use of this miRNA SNP, so as to facilitate conquering HCC.

Investigation of allelic heterogeneity of the CCK‐A receptor gene in paranoid schizophrenia

The cholecystokinin type A receptor (CCKAR) gene has been found to be associated with positive symptoms in patients with schizophrenia but the results reported to date are inconsistent. Considering the involvement of allelic heterogeneity in poor replication of the CCKAR finding, we genotyped five single nucleotide polymorphisms (SNPs) located in the 5' putative regulatory region of the CCKAR gene in a Chinese case-control sample and then applied the 5-SNP haplotype analysis to extract allelic heterogeneity information. The results showed that three individual haplotypes were strongly associated with increased risk of schizophrenia (corrected P = 2.9 × 10(-4), P = 2.5 × 10(-5), and P = 1.4 × 10(-5), respectively) and their combination gave an odds ratio (OR) of 6.12 with 95% CI 3.67-10.21 (P = 6.7 × 10(-15)). The haplotypes were also associated with some clinical symptoms including hallucination, suspiciousness, and hostility. Our work provided further evidence in support of the CCKAR hypothesis of schizophrenia and also suggested that haplotype-based association analysis may be a powerful approach for identification of allelic heterogeneity of a disease-underlying gene, which is very likely to be attributable to poor replication of an initial finding due to the reduction of sample power and the complexity of genetic architectures.

Genetic association and identification of a functional SNP at GSK3β for schizophrenia susceptibility

ObjectiveGSK3β is a key gene in neurodevelopment, and also an important target of antipsychotics. Several lines of evidence including association and gene expression studies have suggested GSK3β as a susceptibility gene for schizophrenia, but the underlying genetic mechanism is still unknown. In this study, we test whether the genetic variants in GSK3β contribute to the risk of schizophrenia in Chinese population. MethodsWe first conducted an association analysis of 9 representative SNPs spanning the entire genomic region of GSK3β in two independent Han Chinese case–control samples from southwestern China (the Kunming sample and the Yuxi sample, a total of 2550 subjects).Then using EMSA and reporter gene assays, we tested the functional impact of the identified risk SNP on transcriptional factor binding affinity and promoter activity. ResultsWe observed weak allelic associations of three GSK3β SNPs (rs3755557, rs7431209 and rs13320980) with schizophrenia in the combined Han Chinese samples. Further analysis using genotypes (under recessive genetic model) supported the association of rs3755557 (p=0.01, corrected), which is located in the GSK3β promoter region. The functional assays demonstrated that the risk SNP (rs3755557) could influence the transcription factor binding affinities, resulting in a higher promoter activity of the risk allele. ConclusionOur findings suggest that GSK3β is likely a risk gene for schizophrenia, and its expression alteration caused by the risk SNP in the promoter region may contribute to the etiology of schizophrenia.

MicroRNAs and target site screening reveals a pre-microRNA-30e variant associated with schizophrenia

MicroRNAs (miRNAs) are short, non-coding RNAs that regulate the stability and translation of mRNA targets. Increasing evidence suggests that miRNAs could be involved in the initiation and progression of neuropsychiatric disorders. Prior to this study, six miRNAs had been reported to show a significantly abnormal expression level in schizophrenic brains. Also, common single nucleotide polymorphisms within two miRNA transcripts have shown genetic associations with schizophrenia. However, it remains largely unknown whether variants in these miRNA genes and/or in their target sites are associated with schizophrenia. Here, we selected the above eight miRNAs, plus 15 of their experimentally validated target sites, as candidate susceptibility factors for schizophrenia, for mutation screening and further association studies in Chinese case–control samples. We identified a new potentially functional variant ss178077483 located in the pre-mir-30e, which was strongly associated with schizophrenia (allelic P = 0.00017; genotypic P = 0.00015), with an odds ratio of 4.952 (95% confidence interval: 1.887–12.998). We also demonstrated that this new variant ss178077483, combined with mir-30e rs7556088 and mir-24-MAPK14 rs3804452, showed a weak gene–gene interaction for schizophrenia risk ( P = 0.001). In addition, analysis of gene expression demonstrated that expression of the mature mir-30e in the peripheral leukocytes was significantly higher in patients' group than in the control group ( P = 6.79e–7).This is the first study to indicate that mir-30e ss178077483 plays a role in schizophrenia susceptibility. It suggests that the contribution of mir-30e to the processes that lead to schizophrenia should be further investigated.

Association and expression study of synapsin III and schizophrenia

The synapsin III gene, SYN3, which belongs to the family of synaptic vesicle-associated proteins, has been implicated in the modulation of neurotransmitter release and in synaptogenesis, suggesting a potential role in several neuropsychiatric diseases. The human SYN3 gene is located on chromosome 22q12-13, a candidate region implicated in previous linkage studies of schizophrenia. However, association studies of SYN3 and schizophrenia have produced inconsistent results. In this study, four SYN3 SNPs (rs133945 (−631 C > G), rs133946 (−196 G > A), rs9862 and rs1056484) were tested in three sets of totally 3759 samples that comprise 655 affected subjects and 626 controls in the Irish Case-Control Study of Schizophrenia (ICCSS), 1350 samples incorporating 273 pedigrees in the Irish Study of High Density Schizophrenia Families (ISHDSF), and 564 unrelated schizophrenia patients and 564 healthy individuals in a Chinese case-control sample. The expression levels of SYN3 in schizophrenic patients and unaffected controls were compared using postmortem brain cDNAs provided by the Stanley Medical Research Institute (SMRI). There was no significant association in either the Irish or Chinese case-control samples, nor in the combined samples. Consistent with this finding, we did not find any significant difference in allele or haplotype frequencies when we used the pedigree disequilibrium test to analyze the Irish family sample. In the expression studies, no significant difference ( p = 0.507) was observed between patients and controls. Both the association studies and expression studies didn’t support a major role for SYN3 in the susceptibility of schizophrenia in Irish and Chinese populations.

No association of the rs4646396 SNP in the PEMT locus with schizophrenia in a Chinese case–control sample

The present study included a total of 628 patients with schizophrenia and 588 healthy controls to replicate the genetic association between the PEMT gene and schizophreia. However, our results in this study failed to confirm our earlier finding that the C allele was preferentially transmitted by parents to their offspring affected with schizophrenia in a family-based study among the Chinese population.

P03-222 A weak association of the CLDN5 locus with schizophrenia in Chinese case-control samples

Background:An increasing number of studies have described the relationship between velo-cardio-facial syndrome (VCFS) and schizophrenia. in a family-based study, we found that rs10314, a single nucleotide polymorphism (SNP) present in the 3’-flanking region of the CLDN5 gene, was associated with schizophrenia among a Chinese population. High false positive rate is a common problem with the association study of human diseases. It is very important to replicate an initial finding with different samples and experimental designs.Methods:A total of 749 patients with schizophrenia and 383 age and sex matched healthy control subjects in Chinese population were recruited. PCR-based RFLP protocol was applied to genotype rs10314 to see its disease association.Results:The χ2 goodness-of-fit test showed that the genotypic distributions of rs10314 were in Hardy-Weinberg equilibrium in both the patient group (χ2=1.12, P=0.289) and the control group (χ2=0.22, P=0.639). rs10314 was associated with schizophrenia with an odds ratio (OR) of 1.32 in the male subjects (χ2=5.45, P=0.02, 95% CI 1.05-1.67) but not in the female subjects (χ2=0.64, P=0.425, OR=1.14, 95% CI 0.83-1.57). the χ2 test showed a genotypic association only for combined samples (χ2=7.80, df=2, P=0.02). SNP rs10314 is a G to C base change. Frequency of the genotypes containing the C allele was significantly higher in the patient group than in the control group.Conclusions:The present work shows that the CLDN5 gene polymorphism is more likely to be involved in schizophrenic men than women, suggesting that this gene may contribute to the gender differences in schizophrenia.

Narcotic antagonists in drug dependence: pilot study showing enhancement of compliance with SYN-10, amino-acid precursors and enkephalinase inhibition therapy

We decided to test the hypothesis that possibly by combining a narcotic antagonist and amino-acid therapy consisting of an enkephalinase inhibitor (d-phenylalanine) and neurotransmitter precursors (l-amino- acids) to promote neuronal dopamine release might enhance compliance in methadone patients rapidly detoxified with the narcotic antagonist Trexan® (Dupont, Delaware). In this regard, Thanos et al. [J. Neurochem. 78 (2001) 1094] and associates found increases in the dopamine D2 receptors (DRD2) via adenoviral vector delivery of the DRD2 gene into the nucleus accumbens, significantly reduced both ethanol preference (43%) and alcohol intake (64%) of ethanol preferring rats, which recovered as the DRD2, returned to baseline levels. This DRD2 overexpression similarly produced significant reductions in ethanol non-preferring rats, in both alcohol preference (16%) and alcohol intake (75%). This work further suggests that high levels of DRD2 may be protective against alcohol abuse [JAMA 263 (1990) 2055; Arch, Gen. Psychiatr. 48 (1991) 648]. The DRD2 A1 allele has also been shown to associate with heroin addicts in a number of studies. In addition, other dopaminergic receptor gene polymorphisms have also associated with opioid dependence. For example, Kotler et al. [Mol. Phychiatr. 3 (1997) 251] showed that the 7 repeat allele of the DRD4 receptor is significantly overpresented in the opioid-dependent cohort and confers a relative risk of 2.46. This has been confirmed by Li et al. [Mol. Psychiatry 2 (1997) 413] for both the 5 and 7 repeat alleles in Han Chinese case control sample of heroin addicts. Similarly Duaux et al. [Mol. Psychiatry 3 (1998) 333] in French Heroin addicts, found a significant association with homozygotes alleles of the DRD3-Bal 1. A study from NIAAA, provided evidence which strongly suggests that DRD2 is a susceptibility gene for substance abusers across multiple populations (2003). Moreover, there are a number of studies utilizing amino-acid and enkephalinase inhibition therapy showing reduction of alcohol, opiate, cocaine and sugar craving behavior in human trials (see Table 1). Over the last decade, a new rapid method to detoxify either methadone or heroin addicts utilizing Trexan® sparked interest in many treatment centers throughout the United States, Canada, as well as many countries on a worldwide basis. In using the combination of Trexan® and amino-acids, results were dramatic in terms of significantly enhancing compliance to continue taking Trexan®. The average number of days of compliance calculated on 1000 patients, without amino-acid therapy, using this rapid detoxification method is only 37 days. In contrast, the 12 subjects tested, receiving both the Trexan® and amino-acid therapy was relapse-free or reported taking the combination for an average of 262 days (p<0.0001). Thus coupling amino-acid therapy and enkephalinase inhibition while blocking the δ-receptors with a pure narcotic antagonist may be quite promising as a novel method to induce rapid detox in chronic methadone patients. This may also have important ramifications in the treatment of both opiate and alcohol-dependent individuals, especially as a relapse prevention tool. It may also be interesting too further test this hypothesis with the sublingual combination of the partial opiate mu receptor agonist buprenorphrine.

Narcotic antagonists in drug dependence: pilot study showing enhancement of compliance with SYN-10, amino-acid precursors and enkephalinase inhibition therapy

We decided to test the hypothesis that possibly by combining a narcotic antagonist and amino-acid therapy consisting of an enkephalinase inhibitor ( d-phenylalanine) and neurotransmitter precursors ( l-amino- acids) to promote neuronal dopamine release might enhance compliance in methadone patients rapidly detoxified with the narcotic antagonist Trexan ® (Dupont, Delaware). In this regard, Thanos et al. [J. Neurochem. 78 (2001) 1094] and associates found increases in the dopamine D2 receptors (DRD2) via adenoviral vector delivery of the DRD2 gene into the nucleus accumbens, significantly reduced both ethanol preference (43%) and alcohol intake (64%) of ethanol preferring rats, which recovered as the DRD2, returned to baseline levels. This DRD2 overexpression similarly produced significant reductions in ethanol non-preferring rats, in both alcohol preference (16%) and alcohol intake (75%). This work further suggests that high levels of DRD2 may be protective against alcohol abuse [JAMA 263 (1990) 2055; Arch, Gen. Psychiatr. 48 (1991) 648]. The DRD2 A1 allele has also been shown to associate with heroin addicts in a number of studies. In addition, other dopaminergic receptor gene polymorphisms have also associated with opioid dependence. For example, Kotler et al. [Mol. Phychiatr. 3 (1997) 251] showed that the 7 repeat allele of the DRD4 receptor is significantly overpresented in the opioid-dependent cohort and confers a relative risk of 2.46. This has been confirmed by Li et al. [Mol. Psychiatry 2 (1997) 413] for both the 5 and 7 repeat alleles in Han Chinese case control sample of heroin addicts. Similarly Duaux et al. [Mol. Psychiatry 3 (1998) 333] in French Heroin addicts, found a significant association with homozygotes alleles of the DRD3-Bal 1. A study from NIAAA, provided evidence which strongly suggests that DRD2 is a susceptibility gene for substance abusers across multiple populations (2003). Moreover, there are a number of studies utilizing amino-acid and enkephalinase inhibition therapy showing reduction of alcohol, opiate, cocaine and sugar craving behavior in human trials (see Table 1). Over the last decade, a new rapid method to detoxify either methadone or heroin addicts utilizing Trexan ® sparked interest in many treatment centers throughout the United States, Canada, as well as many countries on a worldwide basis. In using the combination of Trexan ® and amino-acids, results were dramatic in terms of significantly enhancing compliance to continue taking Trexan ®. The average number of days of compliance calculated on 1000 patients, without amino-acid therapy, using this rapid detoxification method is only 37 days. In contrast, the 12 subjects tested, receiving both the Trexan ® and amino-acid therapy was relapse-free or reported taking the combination for an average of 262 days ( p<0.0001). Thus coupling amino-acid therapy and enkephalinase inhibition while blocking the δ-receptors with a pure narcotic antagonist may be quite promising as a novel method to induce rapid detox in chronic methadone patients. This may also have important ramifications in the treatment of both opiate and alcohol-dependent individuals, especially as a relapse prevention tool. It may also be interesting too further test this hypothesis with the sublingual combination of the partial opiate mu receptor agonist buprenorphrine.

ACT and UCH-L1 polymorphisms in Parkinson's disease and age of onset.

alpha1-Antichymotrypsin (ACT) and ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) have been suggested as susceptibility factors for Parkinson's disease (PD). We replicated these findings in a Chinese case-control sample consisting of 160 PD cases and 160 carefully matched control subjects. Genotypes were determined using polymerase chain reaction and BstN1 or Rsa1 restriction enzyme assay. Analysis showed no significant difference between PD patients and controls for genotype or allele frequencies of the ACT and UCH-L1 S18Y polymorphisms. UCH-L1 S18Y polymorphism carriers, however, were found to be significantly less frequent in early-onset PD patients with a reduced risk of 0.557 (95% C.I. = 0.314-0.985; P = 0.043). These data suggest that ACT polymorphism does not influence the risk for developing PD. UCH-L1 S18Y polymorphism, however, may be a weak protective factor against early-onset PD.

Association analysis of the dopamine D4 gene exon III VNTR and heroin abuse in Chinese subjects.

Although social and cultural influences are clearly important, family, twin and adoption studies indicate that genes contribute significantly to substance abuse. Substance abuse is associated with novelty seeking, a heritable human personality trait which may be influenced by alleles of the dopamine D4 (DRD4) gene exon III VNTR. Consequently Kotler et al analysed the DRD4 VNTR in opiate-dependent subjects from Israel, and found a significant excess of the 7-repeat allele. We have attempted to replicate this finding using a Han Chinese case-control sample of 121 heroin-dependent subjects and 154 normal controls. We found two 7-repeat alleles which occurred exclusively in the patient group, and overall there was an excess of longer alleles, which did not reach significance (chi 2 = 7.04; P = 0.07). When the D4 VNTR was divided into 'long' (5-7 repeats) and 'short' (2-4 repeats), a significant excess of long alleles was observed in the patient group (P = 0.023, one-tailed), with an odds ratio of 2.30 (95% CI 1.07-4.93). We conclude that our findings support the hypothesis that alleles of the DRD4 exon III VNTR are susceptibility factors for heroin abuse.