Polymorphism of the Serotonin 2A Receptor Gene (5HTR2A) and Personality Traits

The individual variation of temperament features (such as anxiety, neuroticism, harm avoidance) is determined, among other things, by allele polymorphism of genes involved in serotonin metabolism and has earlier been associated with the insertion/deletion polymorphism of the serotonin transporter gene. Polymorphic alleles of the serotonin 2A receptor gene (5HTR2A) were tested for association with personality traits assessed in several tests. The T102C and A1438G polymorphisms were associated with variation in emotionality, activity, and sociability, which are integral characteristics of temperament. With each polymorphism, differences were significant only between heterozygotes and homozygotes. Carriers of T102C genotype A1/A2 displayed a lower level of anxiety-related traits, a higher score on the Hypomania scale, and a lower score on the Social Introversion scale and were assumed to have higher activity and sociability. Carriers of A1438G genotype A/G differed from homozygotes G/G in having a lower level of social introversion and a lower score on the No Close Friends scale, which testified to higher sociability of heterozygotes. Thus, the polymorphic alleles of 5HTR2A proved to be associated with personality traits in mentally healthy people.     

绝经后女性CYP19基因Val80及OPG基因A163G多态性与骨密度的相关性研究

探讨细胞色素P450 19 (CYP19) 基因Val80多态性及护骨素(OPG) 基因A163G多态性与绝经后女性骨密度 (BMD) 的关系。随机选择居住在重庆的绝经后女性200例, 采用多聚酶链反应-限制性片段长度多态性法检测Val80及A163G多态性, 采用Norland公司XR-46系列双能X线骨密度仪测量股骨近端及腰椎BMD。 200名绝经后女性中Val80基因型GG、GA及AA的频率分别为19.5％、44.5％及36.0％; A163G基因型GG、GC 及CC的频率分别为: 13.0％, 42.0％及45.0％; 基因型频率分布均符合Hardy-Weinberg平衡 (P＞0.05)。协方差分析及多元逐步回归分析显示CYP19基因第3外显子Val80多态性与绝经后女性BMD无相关性 (P＞0.05)。除大转子外, A163G位点AG/GG/AG+GG基因型者股骨颈、Ward’s三角及腰椎BMD均较AA基因型者低, A163G基因型与股骨颈、Ward’s三角及腰椎BMD有相关性 (P＜0.05)。OPG基因启动子区A163G多态性分布存在明显的种族差异, 且与绝经后女性BMD有一定关联, AA型对BMD具有一定的保护作用, G等位基因是BMD降低的危险因素。     

No correlation between A(-1438)G polymorphism in 5-HT2A receptor gene promoter and the density of frontal cortical 5-HT2A receptors in schizophrenia

The A(-1438)G promoter polymorphism of the 5-hydroxytryptamine 2a receptor (5-HT2AR) gene and its influence on the cortical density of 5-HT2AR was studied using brain tissue donated at autopsy from 58 schizophrenic and 64 non-schizophrenic subjects. A linkage between genotypes for the A(-1438)G and a T102C polymorphic site identified in a previous study was observed. Our data suggest no association of the A(-1438)G polymorphism with schizophrenia and no effect of the promoter genotype upon 5-HT2AR densities in either the schizophrenic or non-schizophrenic groups.     

Polymorphism of the serotonin 2A receptor gene (5HTR2A) and personality traits

The interindividual variation of temperament features (such as anxiety, neuroticism, harm avoidance) is determined, in particular, by allele polymorphism of genes involved in serotonin metabolism and has earlier been associated with the insertion/deletion polymorphism of the serotonin transporter gene. Polymorphic alleles of the serotonin 2A receptor gene (5HTR2A) were tested for association with personality traits assessed with several tests. The T102C and A1438G polymorphisms were associated with a variation in emotionality, activity, and sociability, which are integral characteristics of temperament. With each polymorphism, differences were significant only between heterozygotes and homozygotes. Carriers of T102C genotype A1/A2 displayed a lower level of anxiety-related traits, a higher score on scale Hypomania, and a lower score on scale Social Introversion and were assumed to have higher activity and sociability. Carriers of A1428G genotype A/G differed from homozygotes G/G in having a lower level of social introversion and a lower score on scale No close friends, which testified to higher sociability of heterozygotes. Thus, the polymorphic alleles of SHTR2A proved to be associated with personality traits in mentally healthy people.     

'Smoking genes': a genetic association study

Some controversy exists on the specific genetic variants that are associated with nicotine dependence and smoking-related phenotypes. The purpose of this study was to analyse the association of smoking status and smoking-related phenotypes (included nicotine dependence) with 17 candidate genetic variants: CYP2A6*1×2, CYP2A6*2 (1799T>A) [rs1801272], CYP2A6*9 (-48T>G) [rs28399433], CYP2A6*12, CYP2A13*2 (3375C>T) [rs8192789], CYP2A13*3 (7520C>G), CYP2A13*4 (579G>A), CYP2A13*7 (578C>T) [rs72552266], CYP2B6*4 (785A>G), CYP2B6*9 (516G>T), CHRNA3 546C>T [rs578776], CHRNA5 1192G>A [rs16969968], CNR1 3764C>G [rs6928499], DRD2-ANKK1 2137G>A (Taq1A) [rs1800497], 5HTT LPR, HTR2A -1438A>G [rs6311] and OPRM1 118A>G [rs1799971]. We studied the genotypes of the aforementioned polymorphisms in a cohort of Spanish smokers (cases, N = 126) and ethnically matched never smokers (controls, N = 80). The results showed significant between-group differences for CYP2A6*2 and CYP2A6*12 (both P<0.001). Compared with carriers of variant alleles, the odds ratio (OR) for being a non-smoker in individuals with the wild-type genotype of CYP2A6*12 and DRD2-ANKK1 2137G>A (Taq1A) polymorphisms was 3.60 (95%CI: 1.75, 7.44) and 2.63 (95%CI: 1.41, 4.89) respectively. Compared with the wild-type genotype, the OR for being a non-smoker in carriers of the minor CYP2A6*2 allele was 1.80 (95%CI: 1.24, 2.65). We found a significant genotype effect (all P≤0.017) for the following smoking-related phenotypes: (i) cigarettes smoked per day and CYP2A13*3; (ii) pack years smoked and CYP2A6*2, CYP2A6*1×2, CYP2A13*7, CYP2B6*4 and DRD2-ANKK1 2137G>A (Taq1A); (iii) nicotine dependence (assessed with the Fagestrom test) and CYP2A6*9. Overall, our results suggest that genetic variants potentially involved in nicotine metabolization (mainly, CYP2A6 polymorphisms) are those showing the strongest association with smoking-related phenotypes, as opposed to genetic variants influencing the brain effects of nicotine, e.g., through nicotinic acetylcholine (CHRNA5), serotoninergic (HTR2A), opioid (OPRM1) or cannabinoid receptors (CNR1).     

5-羟色胺受体基因多态性位点与海洛因依赖的关联性研究

目的：5-HT（5-hydroxytryptamine,5-HT）参与了多种中枢神经活动的生理过程,其功能异常可以影响很多行为障碍,已有研究显示,5-HT水平与多种精神疾病密切相关。5-HT受体及其转运体基因在海洛因依赖发生发展中起到了重要的作用,是海洛因依赖的主要候选基因。探讨5羟色胺2A受体（Serotonin 2A receptor,HTR2A）基因启动子区-1438A/G（rs6311）、外显子区102T/C（rs6313）与5羟色胺1B受体（Serotonin 1B receptor,HTR1B）基因外显子区861G/C（rs6296）3个单核苷酸多态性和海洛因依赖的关联性分析。方法：严格按照诊断标准,选取无亲缘关系的海洛因依赖个体616例及健康个体600例提取基因组DNA,采用PCR-RFLP方法检测rs6311、rs6313和rs6296 3个SNPs位点的基因型频率,采用SPSS16.0软件分析各位点等位基因、基因型频率在病例-对照组间差异。结果：HTR2A基因rs6311和HTR1B基因rs6296位点的等位基因及基因型频率分布在2组间存在统计学差异（P〈0.05）,病例组rs6311位点的等位基因A频率显著高于对照组（X2=5.436,P=0.020,OR=1.208,CI=1.031~1.417）,rs6296位点的等位基因C频率显著高于对照组（X2=12.116,P=0.000,OR=1.329,CI=1.132~1.560）。连锁不平衡检验结果显示,HTR2A基因rs6311、rs6313位点处于不连锁状态,D＇〈0.5。结论：HTR2A基因rs6311和HTR1B基因rs6296多态性可能与海洛因成瘾有关,携带有rs6311 A等位基因与rs6296 C等位基因的人可能更容易对海洛因产生依赖。我们的研究为海洛因依赖易感人群筛选及药物靶向治疗提供了理论依据。     

PPARGC1A基因Thr394Thr/Gly482Ser多态性与2型糖尿病的关联研究

对344例2型糖尿病患者和307名正常人的PPARGC1A基因单核苷酸多态性rs2970847(Thr394Thr)和rs8192678(Gly482Ser)与2型糖尿病的关系进行了单标记和单体型关联分析以及Logistic回归分析。在单标记分析中,对照组与病例组Thr394Thr的基因型和等位基因频率有显著差异(基因型, P =0.006; 等位基因, P < 0.001); Logistic回归和单体型分析表明, Thr394Thr的AA基因型及Thr394(ACA)-Ser482单体型增加患2型糖尿病的风险。Gly482Ser的基因型和等位基因频率在对照组与病例组间无显著差异。PPARGC1A基因是湖北汉人的一个2型糖尿病易感基因。     

Prostate-specific antigen and 17-hydroxylase polymorphic genotypes in patients with prostate cancer and benign prostatic hyperplasia

We investigated the association of prostate cancer (PCa) and benign prostatic hyperplasia (BPH) with genetic polymorphisms in prostate-specific antigen (PSA) (-158 G/A) and 17-hydroxylase (CYP17) (-34 T/C) genes in a Turkish population. In this study, we investigated the distribution of these polymorphisms in 148 PCa patients, 136 BPH patients, and 102 healthy individuals as controls. The polymorphisms were analyzed using polymerase chain reaction-restriction fragment length polymorphism assay. Genotype and allele frequencies were calculated, and their associations with PCa or BPH risk are assayed. The frequency of PSA gene GA and GG genotypes was significantly higher in PCa patients than in controls (p = 0.017 and p = 0.019, respectively). GG genotype was also associated with BPH (p = 0.033). In a case analysis, according to Gleason score, the association of PSA gene GG genotype with Gleason score >7 was near to statistical significance (odds ratio, 2.94; 95% confidence interval, 0.95-9.28). There was also an association between CYP17 polymorphism and BPH (p = 0.004). No association was observed between PCa and CYP17 gene polymorphism. These data demonstrate that PSA gene promoter variation may play a significant role in the development of PCa and BPH, and that CYP17 gene polymorphism may be associated with BPH in the Turkish population studied.     

CYP1A2 polymorphism (C > A at position -163) in Ovambos, Koreans and Mongolians

Cytochrome P450 1A2 (CYP1A2) plays an important role in metabolizing drugs and xenobiotics, and is a possible participant in the development of several human diseases. Recent studies have shown that genetic polymorphism of -163 C > A single nucleotide mutation of CYP1A2 increases the risk of myocardial infarction and modulates CYP1A2 activity. In this study, we investigated the frequency of the -163 C > A mutation in Ovambos (n = 177), Koreans (n = 250) and Mongolians (n = 153) and compared our results with other studies. Detection of this single nucleotide polymorphism was by polymerase chain reaction-restriction fragment length polymorphism analysis (PCR-RFLP). The frequencies of mutation (CYP1A2*-163A) in the Ovambos, Koreans and Mongolians were 0.46, 0.32 and 0.21, respectively. Ovambos showed a relatively higher frequency of mutation, similar to that of Tanzanians, while the Mongolians showed the lowest frequency of all study groups, including those from previous studies. This study is the first to investigate the distribution of the CYP1A2 (-163 C > A single nucleotide polymorphism) mutant allele in Ovambo, Korean and Mongolian populations.     

Analysis of serotonin receptor 2A gene (HTR2A): Association study with autism spectrum disorder in the Indian population and investigation of the gene expression in peripheral blood leukocytes

Several studies suggest involvement of serotoninergic system in the pathophysiology of Autism Spectrum Disorder (ASD). The 5-HT receptor binding studies using ³H-lysergic acid diethylamide (³H-LSD) and linkage analysis provided evidences to consider HTR2A as a potential candidate gene for ASD. The three SNPs, −1438A/G (rs6311), 102T/C (rs6313) and 1354C/T (rs6314) of HTR2A have been well studied in the etiology of various neuropsychiatric disorders. But studies on association of this gene with ASD are limited to two reports from American and Korean populations. Additionally there are reports, which demonstrated paternal imprinting of HTR2A with expression from only one allele. So far no reports are available on HTR2A and its association with any neuropsychiatric disorders from Indian population. Therefore, the present study investigates association of the above mentioned three markers of HTR2A with ASD in Indian population using population and family-based approaches. The study also deals with allelic expression pattern of HTR2A in Peripheral Blood Leukocytes (PBLs) to understand the parental imprinting status. The genotyping analyses were carried out for probands, parents and controls. The subsequent association analyses did not show association of these markers with ASD. So, HTR2A is unlikely to be a genetic marker for ASD in Indian population. The expression analyses showed absence of monoallelic expression, suggesting lack of parental imprinting of HTR2A gene. However, we noticed methylation of the CpG sites at −1438A/G and 102T/C loci of HTR2A gene. Further bioinformatics analysis revealed absence of CpG islands in the promoter of the gene supporting biallelic expression pattern of HTR2A in PBLs.     

Association of SLC18A1, TPH1, and RELN gene polymorphisms with risk of paranoid schizophrenia

A biochip was developed to examine the polymorphisms of genes associated with schizophrenia risk, including DISC1, RELN, ZNF804A, PLXNA2, COMT, SLC18A1, CACNA1C, ANK2, TPH1, PLAA, and SNAP-25. Allele and genotype frequencies of the genes were determined in 198 schizophrenics and 192 healthy subjects from Bashkortostan (ethnic Russians and Tatars). The frequencies of allele A (p = 0.007) and genotype AA (p = 0.002) of the rs2270641 A>C polymorphism of SLC18A1 in the patients with paranoid schizophrenia was lower than in the healthy subjects. The frequency of genotype AA of the rs1800532 C>A polymorphism of TPH1 in the schizophrenics was higher than in the healthy subjects (p = 0.036). Compared with the healthy subjects, the ethnic Tatar patients with paranoid schizophrenia had a lower frequency of allele C of the rs7341475 C>T polymorphism of RELN (p = 0.039) and a higher frequency of genotype AA of the rs1800532 C>A polymorphism of TPH1 (p = 0.019, OR = 2.52, CI 1.18-5.38). The frequency of allele C (p = 0.0001) and genotype GC (p = 0.0001) of the rs1327175 G>C polymorphism of PLXNA2 was elevated in the patients with a family history of paranoid schizophrenia. Based on the results, the SLC18A1, TPH1, and RELN polymorphisms were associated with risk of schizophrenia.     

Frequencies of four genetic polymorphisms in the CYP1A2 gene in Turkish population

Cytochrome P450 (CYP) 1A2 gene is involved in the metabolic activation of several carcinogens and altered metabolization of some clinically used drugs. We aimed to investigate the distributions of genetic polymorphisms -3860 (G/A)(CYP1A2*1C) and -2467 (T/del)(CYP1A2*1D) in the 5'-flanking region and -739 (T/G)(CYP1A2*1E) and -163(C/A)(CYP1A2*1F) in the first intron of the CYP1A2 gene in 110 unrelated healthy Turkish volunteers by PCR-RFLP technique. The frequencies of each polymorphism in Turkish population were found as 0.04, 0.92, 0.01, 0.27 for CYP1A2*1C, CYP1A2*1D, CYP1A2*1E, CYP1A2*1F, respectively. Compared with other populations, CYP1A2*1D has been found to be significantly increased in Turkish population. On the other hand, in general, the frequencies of the other polymorphisms were concordant with those in the Egyptian and Caucasian populations, and were different from those in the Japanese, Chinese and Ethiopian populations. Our results suggest that due to increased frequency of CYP1A2*1D in Turkish population, functional significance of CYP1A2*1D should be evaluated. It might be screened to determine the relationship between CYP1A2*1D and CYP1A2 related drug metabolisms in associated groups.     

Association analysis of gene polymorphism in alcohol metabolizing enzymes with risk for coronary atherosclerosis

The allele and genotype distribution of two alcohol dehydrogenase genes ADH1B (exon 3 polymorphism A/G (47His)), ADH7 (intron 5 polymorphism G/C) and cytochrome P450 2E1 gene (CYP2E1; 5'-flanking region G/C and intron 6 T/A polymorphisms) were examined in Russian (Tomsk, n = 125) healthy population and in coronary atherosclerosis patients (CA, n = 92). The genotype frequencies followed the Hardy-Weinberg equilibrium and the alleles were in linkage equilibrium or gametic equilibrium in the control sample. Only two CYP2E1 gene polymorphisms were in linkage disequilibrium. The frequencies of the derived alleles at ADH1B (*G (+MslI) allele), CYP2E1 (**C2 (+PstI) allele) and CYP2E1 (*C (-Dra I)2 allele) were 8.48 +/- 1.86%; 1.20 +/- 0.69% and 10.00 +/- 1.90%, respectively. The 2ADH7 gene polymorphism showed a high level of heterozygosity; the frequency of the ADH7*C (-Sty I) allele was 44.58 +/- 3.21%. A significantly higher frequency of CYP2E1 (*C2 (+Pst I)) allele has been revealed in the CA group (P = 0.043; OR = 4.23; 95% CI 1.03-20.01). The tendency to significant effect of A1A2 genotype in ADH1B Msl 1 polymorphism was observed for systolic blood pressure in the control group (P = 0.068). The statistically significant two-way interaction effects of ADH7 StyI and CYP2E1 DraI on diastolic blood pressure (P = 0.029) and on the serum high density lipoprotein level (P = 0,042) were also revealed. Association of A1A2 genotype in ADHIB Msl I polymorphism with reduced amount in a serum of a very low density lipoprotein level (P = 0.045) have also been shown. This may result from multifunctional activity of alcohol metabolizing enzymes and their involvement in many metabolic and free radical reactions in the body.     

BanI polymorphism of cytosolic phospholipase A2 gene is associated with age at onset in male patients with schizophrenia and schizoaffective disorder

The enzymes phospholipases A2 are believed to be involved in the pathology of schizophrenia. We investigated allelic and genotype frequencies of PLA2G4A BanI polymorphism and the rs4375 in PLA2G6A in Croatian schizophrenic patients (n=81) and controls (n=182), using PCR/RFLP. Genotype and allelic frequencies of both loci, alone or in combination did not show significant difference (chi2-test). Allele-wise and genotype-wise meta-analyses of BanI polymorphism in case-control and family-based studies also revealed no significant association with schizophrenia. Multiple logistic regression analyses revealed statistically significant association between several items from PANSS general psychopathology scale and BanI polymorphism in PLA2G4A. BanI polymorphism further showed a significant impact on mean age of the onset of disease in males (betaA1=0.351, P=0.021; Spearman's rA1=0.391, P=0.010) indicating lower mean age at admission in homozygous A2A2 males.     

Analysis of serotonin receptor 2A gene (HTR2A): Association study with autism spectrum disorder in the Indian population and investigation of the gene expression in peripheral blood leukocytes

Several studies suggest involvement of serotoninergic system in the pathophysiology of Autism Spectrum Disorder (ASD). The 5-HT receptor binding studies using ³H-lysergic acid diethylamide (³H-LSD) and linkage analysis provided evidences to consider HTR2A as a potential candidate gene for ASD. The three SNPs, −1438A/G (rs6311), 102T/C (rs6313) and 1354C/T (rs6314) of HTR2A have been well studied in the etiology of various neuropsychiatric disorders. But studies on association of this gene with ASD are limited to two reports from American and Korean populations. Additionally there are reports, which demonstrated paternal imprinting of HTR2A with expression from only one allele. So far no reports are available on HTR2A and its association with any neuropsychiatric disorders from Indian population. Therefore, the present study investigates association of the above mentioned three markers of HTR2A with ASD in Indian population using population and family-based approaches. The study also deals with allelic expression pattern of HTR2A in Peripheral Blood Leukocytes (PBLs) to understand the parental imprinting status. The genotyping analyses were carried out for probands, parents and controls. The subsequent association analyses did not show association of these markers with ASD. So, HTR2A is unlikely to be a genetic marker for ASD in Indian population. The expression analyses showed absence of monoallelic expression, suggesting lack of parental imprinting of HTR2A gene. However, we noticed methylation of the CpG sites at −1438A/G and 102T/C loci of HTR2A gene. Further bioinformatics analysis revealed absence of CpG islands in the promoter of the gene supporting biallelic expression pattern of HTR2A in PBLs.     

Influence of the genetic polymorphism in the 5'-noncoding region of the CYP1A2 gene on CYP1A2 phenotype and urinary mutagenicity in smokers

The functional significance of genetic polymorphisms on tobacco smoke-induced CYP1A2 activity was examined. The influence of three polymorphisms of the cytochrome P450 1A2 gene (CYP1A2) (-3860 G-->A (allele *1C), -2467 T-->delT (allele *1D), -163C-->A (allele *1F)), located in the 5'-noncoding promoter region of the gene, on CYP1A2 activity (measured as caffeine metabolic ratio, CMR), was studied in Caucasian current smokers (n=95). Tobacco smoke intake was calculated from the number of cigarettes/day. Also, studied was the influence of these CYP1A2 genotypes on smoking-associated urinary mutagenicity, detected in Salmonella typhimurium strain YG1024 with S9 mix, considering the urinary excretion of nicotine plus its metabolites as an internal indicator of tobacco smoke exposure. Smokers with at least one of the variant alleles CYP1A2 -3860A and -2467 delT showed a significantly increased CYP1A2 CMR (-3860 G/A versus G/G, p<0.05; -2467 delT/delT versus T/delT and T/T, p<0.01). Multiple regression analysis showed that the increase in CYP1A2 CMR (ln values) was again significantly related to the presence of CYP1A2 variants -2467delT and also to variant -163A (p<0.05), but moderately to -3860A (p=0.084). No influence of the number of cigarettes smoked per day by each subject was found. Heavy smokers (n=48, with urinary nicotine plus its metabolites>or=0.69 mg/mmol creatinine) with variant allele -2467delT or -163A had significantly increased urinary mutagenicity (p<0.01 and <0.05). CYP1A2 genetic polymorphisms are shown to influence the CYP1A2 phenotype in smokers, -2467 T-->delT having the main effect. This information is of interest for future studies assessing the possible role of tobacco smoke-inducible CYP1A2 genotypes as individual susceptibility factors in exposure to carcinogens.     

CYP2D6 and CYP1A1 mutations in the Turkish population

Drugs and carcinogens are substrates of a group of metabolic enzymes including cytochrome p450 enzymes and gluthatione S-transferases. Many of the genes encoding these enzymes exhibit functional polymorphisms that contribute individual cancer susceptibility and drug response. Molecular studies based on these polymorphic enzymes also explain the aetiology of cancer and therapeutic management in clinics. We analysed the cytochrome p4501A1 (CYP1A1) and 2D6 (CYP2D6) variant genotype and allele frequencies by PCR-RFLP in Turkish individuals (n=140). The frequency of the CYP1A1*2A mutant allele was found to be 15.4%, and the CYP2D6*3 and *4 mutant allele (poor metabolizer) frequencies were 2.5% and 13.9%, respectively. This study presents the first results of CYP1A1 and CYP2D6 mutant allele distributions in the Turkish population and these data provide an understanding of epidemiological studies that correlate therapeutic approaches and aetiology of several types of malignancy in Turkish patients.     

Identification of a single nucleotide polymorphism in the TATA box of the CYP2A6 gene: impairment of its promoter activity

Human cytochrome P450 2A6 (CYP2A6) constitutes the major nicotine oxidase, and large interindividual differences are seen in the levels of this enzyme, to a great extent caused by the distribution of several different polymorphic gene variants mainly located in the open reading frame (ORF). In the present study, we report a common polymorphism located in the 5' flanking region of CYP2A6 affecting its expression. DHPLC analysis and complete sequence of the open reading frame of the gene from a Turkish individual revealed a -48T > G substitution disrupting the TATA box. Using dynamic allele-specific hybridization (DASH), genotyping of this novel variant (named CYP2A6*9) was carried out in 116 Swedish, 132 Turkish, and 102 Chinese subjects, and the allele frequencies were found to be 5.2, 7.2, and 15.7%, respectively. The significance of the polymorphism was investigated by the construction of luciferase reporter plasmids containing 135 or 500 bp of the 5'-upstream region of the gene transfected into human hepatoma B16A2 cells. The constructs carrying the -48T > G mutation were only expressed at about 50% of the wild-type alleles. It is concluded that the CYP2A6*9 allele might be one of the most common CYP2A6 variants in Caucasians that alters the levels of enzyme expression.     

Association between promoter variants of interleukin-18 and schizophrenia in a Han Chinese population

An increasing amount of evidence suggests that interleukin-18 (IL-18) plays a pivotal role in the pathophysiology of schizophrenia. However, association between single nucleotide polymorphism of IL-18 and the risk of schizophrenia has not been clarified. This study examined whether two promoter polymorphisms -137 G/C (rs187238) and -607 C/A (rs1946518) of IL-18 were associated with schizophrenia and six clinical symptoms (disorder of perception, thought disorder, disturbance of emotion, disorder of behavior and volition, suicide action, and aggressive action) to provide data for screening high-risk Han Chinese individuals. Three hundred seventy-two schizophrenic patients and 353 healthy controls from a Han Chinese population were examined to assess their genotype and allele frequencies of the two promoter polymorphisms of IL-18. The genotype distributions in both patients and controls were within Hardy-Weinberg equilibrium. No significant differences were observed in the genotype or the allele frequencies of the two single-nucleotide polymorphisms between patients and controls. However, genotype frequencies of -607 C/A showed significant differences between patients and controls in the appearance of perception disorder (χ2 = 6.153, p = 0.046). A significant difference was detected in -137 G/C between patients and controls in the appearance of aggressive action (χ2 = 3.909, p = 0.048). In conclusion, IL-18 gene promoter polymorphisms may not contribute to the susceptibility of schizophrenia in a Han Chinese population, but two single-nucleotide polymorphisms, -137 G/C and -607 C/A, may play a role in the development of perception disorder and aggressive action, respectively.