精神分裂症和亚甲基四氢叶酸还原酶基因的核心家系研究

目的探讨亚甲基四氢叶酸还原酶(MTHFR)基因与中国西北地区汉族精神分裂症的关系。方法应用聚合酶链反应-限制性片段长度多态性方法(PCR-RFLP),检测106个精神分裂症核心家系MTHFR基因的C677T和A1298C多态性,采用单倍体相对风险(HRR)和传递不平衡检验(TDT)分析MTHFR基因与精神分裂症的关系。结果①患者组与父母组MTHFR基因C677T和A1298C多态性基因型频率分布差异无统计学意义(x2=0.369,P>0.05;x2=1.214,P>0.05)。②HRR分析显示C677T、A1298C两位点等位基因在病例组和父母对照组的频数分布差异无统计学意义(x2=0.236,P>0.05;x2=3.327,P>0.05)。③TDT检验未发现C677T和A1298C两位点在精神分裂症中存在传递不平衡(x2=0.243,P>0.05;x2=2.123,P>0.05)。结论未发现MTHFR基因C677T和A1298C多态性与精神分裂症存在关联。     

难治性精神分裂症与亚甲基四氢叶酸还原酶基因多态性的关联分析

目的:探讨难治性精神分裂症与亚甲基四氢叶酸还原酶(MTHFR)基因C677T和A1298C多态性的关系。方法:应用聚合酶链反应-限制性片断长度多态性方法(PCR-RFLP)检测102名正常对照、138例难治性精神分裂症患者及97例非难治性精神分裂症患者MTHFR基因的C677T和A1298C多态性。结果:患者组与对照组,难治组与非难治组C677T、A1298C基因型分布差异均无统计学意义(C677T,χ2=4.83,P=0.09;χ2=1.90,P=0.39;A1298C,χ2=1.50,P=0.47;χ2=3.90,P=0.14),而患者组C677T的T等位基因频率显著高于正常对照组(P=0.04),难治组A1298C的C等位基因频率显著高于非难治组(P=0.04)。677TT/1298AA、677CT/1298AC复合基因型患病相对风险度比677CC/1298AA型显著提高(OR=4.13,95%CI=1.26～13.58,P=0.02;OR=2.95,95%CI=1.23～7.07,P=0.01),而在难治组和非难治组中,复合基因型差异无统计学意义。结论:MTHFR基因677T等位基因和677TT/1298AA、677CT/1298AC复合基因型是精神分裂症发病危险因素,MTHFR基因1298C等位基因可能是难治性精神分裂症的危险因子之一。     

精神分裂症与染色体22q11的连锁不平衡研究

目的 探讨染色体22q11泛有素融合降解1型蛋白基因(UFD1L)和腭心面综合征缺失的核定位信号基因(NLVCF)多态性与精神分裂症的关系。方法 在138例吉林省汉族精神分裂症患者及其健康父母双亲的核心家系中，以聚合酶链反应(PCR)和限制性片段长度多态(RFLP)方法对UFDlL基因rs1547931(G／C碱基改变)和NLVCF基因rs1473109(C／T碱基改变)单核苷酸多态性(SNPs)进行检测。应用基于家系的连锁不平衡方法，包括单体型相对风险分析(HRR)，传递不平衡检验(TDT)及Transmit双位点单体型分析，分析基因型数据。结果 (1)HRR显示UFDlL基因rs1547931与精神分裂症有关联(χ^2=4．260，ν=1，P=0．039)，NLVCF基因rs1473109与精神分裂症无关联；(2)TDT显示UFDlL基因rs1547931与精神分裂症有连锁和关联(χ^2=5．333，ν=1，P=0．021)，NLVCF基因rs1473109与精神分裂症无连锁及关联；(3)Transmit双位点单体型分析显示rs1547931-rs1473109单体型与精神分裂症有关联(χ^2=9．723，ν=3，P=0．021)，rs1547931(C)-rs1473109(T)单体型与精神分裂症呈负相关(χ^2=6．607，ν=1，P=0．01)。结论 精神分裂症患者UFD1L基因本身或其附近的基因可能与精神分裂症的易感性相关。     

精神分裂症和心境障碍混合家系MLC1基因多态性的关联研究

目的在中国汉族人群精神分裂症和心境障碍混合家系中探讨位于22q13的MLC1基因多态性(rs11568171、rs2076137及rs2235349)与精神分裂症、心境障碍的关系。方法在有精神分裂症和心境障碍混合遗传家族史的67个核心家系(包括44个完整的核心家系)中,采用聚合酶链式反应和限制性片断长度多态性(PCR-RFLP)方法,分析MLC1基因上述多态性的基因型及其单体型,进行传递不平衡检验(TDT)。结果患者组与父母组之间,MLC1基因rs11568171T/C、rs2076137T/C及rs2235349T/C多态性等位基因和基因型分布差异无统计学意义(P>0.05),且TDT结果示各多态性在精神分裂症或心境障碍组中父母与患者之间等位基因传递差异均无统计学意义(P>0.05)。单体型TDT显示,精神分裂症患者组中父母与患者之间单体型T-C-T明显传递过少(2=5.0,P<0.05),而单体型C-C-C明显传递过多(2=5.0,P<0.05)。结论在中国汉族人群中MLC1基因可能是精神分裂症的易感基因,但可能不是心境障碍的易感基因。     

肿瘤坏死因子基因与精神分裂症的传递不平衡研究

目的 探讨肿瘤坏死因子-α(TNF-α)基因和肿瘤坏死因子-β(TNF-β)基因与精神分裂症的关系.方法 收集172个广东潮汕地区的精神分裂症核心家系,将172例精神分裂症患者分为偏执型(96例)和非偏执型(76例),用聚合酶链反应-限制性片段长度多态性方法 ,检测所有研究对象的TNF-α的3个多态性位点(-C863A、-G308A、-G238A)和TNF-β+A252G位点的等位基因频率和基因型频率,并进行传递不平衡检验(TDT).结果 (1)单位点TDT检验,TNF-β+A252G位点杂合子父母过多地传递等位基因G给患者(X2=5.49,Pc＜0.05),而TNF-α的3个多态性位点(-C863A、-G308A、-G238A)均未发现传递不平衡.(2)多位点联合进行单体型分析,未显示在精神分裂症核心家系中存在传递不平衡;但在96个偏执型精神分裂症核心家系中,有一种常见单体型[(-863C,-308G,-238G,+252G);X2=7.20,Pc＜0.05]存在偏向传递.结论 在广东潮汕人群中,TNF-α和TNF-β基因与精神分裂症可能存在某些关联,该基因可能是偏执型精神分裂症的易感基因.     

肿瘤坏死因子-β基因+A252G多态性与精神分裂症的关联分析

目的探讨肿瘤坏死因子-β(TNF-β)基因+A252G多态性位点与精神分裂症的关系。方法收集172个来自广东潮汕地区的精神分裂症核心家系,用聚合酶链式反应-限制性片段长度多态性(PCR-RFLP)方法,检测所有研究对象的TNF-β基因+A252G位点的基因频率和基因型,并进行基于单体型的单体型相对风险(HHRR)和传递不平衡检验(TDT)。结果HHRR分析结果显示,精神分裂症患者组与虚拟对照组之间+A252G位点的基因频率差异有统计学意义(2=5.28,P<0.05);TDT结果显示,杂合子父母过多地传递等位基因G给患者(2=5.49,P<0.05),提示该多态位点在精神分裂症中存在传递不平衡;按临床亚型进一步分层分析,+A252G位点只在96个偏执型分裂症家系中存在明显的传递不平衡(2=11.23,P<0.001)。结论在广东潮汕人群中,TNF-β基因+A252G位点与精神分裂症存在连锁,它可能是精神分裂症尤其是偏执型分裂症的易感基因或与之存在连锁不平衡。     

精神分裂症与Xp11区HSU93305基因座的单体型及22 q11～13区相关基因的关联性研究

目的探讨Xp11区HSU93305基因座单体型、22 q11～13区α2肾上腺素能受体(A2αR)基因和儿茶酚-氧-甲基转移酶(COMT)基因多态性与精神分裂症的关联.方法分别提取59个中国汉族核心家系成员(母59名,父56名,精神分裂症患者59例)的DNA,采用基因扩增和限制性片段长度多态性技术,进行HSU93305基因座的单体型研究;选择其中56个父母均存活的家系进行A2αR基因和COMT基因多态性传递不平衡检验(TDT)的研究,并应用复等位基因TDT、基于单体型的单体型相对风险率(HHRR)检验等.结果 (1)Xp11区HSU93305基因座经Msp Ⅰ及Dra Ⅱ酶切后产生四种单体型D1M1,D1M2,D2M1,D2M2.父母组以单体型D2M1频率最高(57.7%);患者组也以D2M1传递率最高(59.0%),其次为D1M2(28.9%),D2M2传递率最低(1.2%).(2)经复等位基因TDT分析,精神分裂症与Xp11区HSU93305基因座相关联(χ2=9.28,v=3,P<0.05);与A2αR基因(χ2=1.09,v=1,P>0.05)和COMT基因(χ2=0.31,v=1,P>0.05)未见关联.(3)经HHRR检验,A2αR基因(χ2=1.21,v=1,P>0.05)和COMT基因(χ2=0.37,v=1,P>0.05)与精神分裂症亦未见关联.结论精神分裂症与HSU93305基因座相关联,其易感基因可能位于Xp11区;与A2αR基因和COMT基因多态性可能无关.     

精神分裂症患者核心家系的5-羟色胺2A受体基因的传递/不平衡检验分析

目的 对精神分裂症的5-羟色胺2A受体(5HTR2A)/T102C多态性作关联研究.方法 采用聚合酶链反应扩增及限制性片段长度多态性的分子生物学技术,对符合精神分裂症诊断标准的92个先证者及其父母组成的核心家系,测定5HTR2A基因分型,进行精神分裂症的5HTR2A/T102C多态性的关联分析和传递/不平衡(TDT)检验.结果 TDT检验结果 提示5HTR2A等位基因2(C102)与精神分裂症之间的相关性(McNemar χ2=4.63,P<0.05),且C102携带者的精神分裂症易患性是非T102携带者的1.88倍[相对风险度(RR)=1.88;χ2(RR)=5.60,P<0.05].结论 提示5HTR2A C102与精神分裂症相关联.     

胱硫醚-β-合成酶基因多态性与精神分裂症核心家系的关联研究

目的:探讨胱硫醚-β-合成酶(cystathionine-beta-synthase,CBS)基因多态性与精神分裂症的关系。方法:采用聚合酶链式反应和DNA测序技术,检测75个精神分裂症核心家系CBS基因T833C、G919A多态性,采用单倍体相对风险度(haplotyperelativerisk,HRR)分析和传递不平衡检验(transmission disequilibrium test,TDT)分析CBS基因多态性与精神分裂症的关系。结果:所有受检者均未发现CBS基因T833C、G919A多态性,但下游8-9内含子33bp处见G→A突变。患者组G→A突变的基因型频率[GG(82.67%),GA(14.67%),AA(2.66%)]与父母组[GG(81.33%),GA(16%),AA(2.67%)]比较差异无统计学意义(χ2=0.29,P>0.05),患者组G→A突变的等位基因频率[G(90%),A(10%)]与父母组[G(89.33%),A(10.67%)]比较差异也无统计学意义(χ2=0.32,P>0.05)。HRR分析未显示G→A突变与精神分裂症有关联(χ2=0.21,P>0.05),TDT分析未见A等位基因在杂合双亲向患病子女的传递中有优势性(χ2=1.80,P>0.05)。结论:CBS基因多态性可能不是精神分裂症的遗传学危险因素。     

精神病混合家系GRIK2基因多态性的关联研究

目的　在中国汉族人群混合家系中探讨GRIK2基因多态性与精神分裂症、心境障碍是否 关联。方法　采用PCR RFLP技术对GRIK2基因多态性rs6922753(T/C)和rs2227283(G/A)分型,进行 传递不平衡检验(TDT)。结果　(1)rs6922753多态性与精神分裂症(χ2=3.13,P>0.05)或心境障碍 (χ2=3.20,P>0.05)无关联,但在发病年龄≤25岁的患者中与两组疾病均相关联(P<0.05);(2) rs2227283多态性与精神分裂症(χ2=9.85,P<0.01)、心境障碍(χ2=13.50,P<0.01)呈显著关联;(3) 双位点TDT提示单体型TG、CA与精神分裂症、心境障碍相关联(P<0.05)。结论　在中国汉族人群 中GRIK2基因或邻近基因可能是精神分裂症和心境障碍的共同易患基因之一,并可能影响发病年龄。     

Linkage disequilibrium between dopamine D1 receptor gene (DRD1) and bipolar disorder.

BACKGROUND: Based on the dopamine hypothesis, the dopamine D1 receptor gene (DRD1) is considered to be a good candidate gene for bipolar disorder (BP). METHODS: In our study, three polymorphisms of the DRD1 gene, -800T/C, -48A/G, and 1403T/C, were analyzed in 286 BP trios. Both the transmission disequilibrium test (TDT) and haplotype TDT were performed on the genotype data to test for the presence of linkage disequilibrium between DRD1 and bipolar disorder. With the extended transmission disequilibrium test (ETDT), we also calculated the maternal transmission and paternal transmission for each allele. RESULTS: Although no association was found for each individual polymorphism, there is a significant association between DRD1 and BP for haplotype TDT analysis (chi(2) = 16.068, df = 3, p =.0011). CONCLUSIONS: These results indicate that DRD1 may play a role in the etiology of bipolar disorder.     

Association and linkage disequilibrium between a functional polymorphism of the dopamine-2 receptor gene and schizophrenia in a genetically homogeneous Portuguese population

A functional polymorphism in the promoter region of the DRD2 gene has been found to be associated with schizophrenia in Japanese(1,2) and Swedish populations.(3) We attempted to replicate these findings in a genetically homogeneous Portuguese population using a family-based study design. Analysis of 78 trios revealed evidence for association between the -141 C Ins allele and schizophrenia using the haplotype relative risk (HRR) method (chi(2) = 9.30, P = 0.0023). Further examination of this sample using an alternative family-based association analysis method, the transmission disequilibrium test (TDT), of 33 informative matings from the Portuguese trios provided evidence for an allelic association and linkage disequilibrium between the insertion allele and schizophrenia (chi(2) = 8.76, P = 0.0031). These consistent results using two alternative family-based association analysis methods replicate the findings of previous reports, and thus further implicate a potential role for the dopamine-2 receptor in the genetic etiology of schizophrenia.     

Transmission disequilibrium test and haplotype analysis of the NOTCH4 gene in Japanese patients with schizophrenia

A recent study reported that the NOTCH4 gene was highly associated with schizophrenia in the British population. To confirm this association for another population, a case-control study was conducted and a transmission disequilibrium test (TDT) analysis was performed on a group of Japanese subjects (235 pairs of schizophrenia patients and controls, and 78 trios consisting of probands and their parents) using two single nucleotide polymorphisms and three microsatellite markers for the NOTCH4 gene. Haplotype analysis was also studied in case-control and family based data sets. In all markers except for (CTG)n (P = 0.012, before correction for multiple testing), no differences were found in the case-control study. The TDT analysis also revealed only a weak transmission disequilibrium in (TTAT)n (genotype-wise P = 0.012). The finding of the present study could not support the original findings that the NOTCH4 gene itself is associated with susceptibility to schizophrenia.     

No association between the putative functional ZDHHC8 single nucleotide polymorphism rs175174 and schizophrenia in large European samples.

BACKGROUND: It has been recently reported that a functional variant in the ZDHHC8 gene encoding a putative palmitoyltransferase directly confers susceptibility to schizophrenia in females (). METHODS: We investigated the putative risk allele (rs175174) in four schizophrenia association samples including a Bulgarian proband and parent sample (474 trios) and three case-control panels of European origin (1028 patients/1253 control subjects) in an attempt to replicate these findings. RESULTS: Our results do not support the hypothesis that genetic variation at rs175174 is associated with increased risk for schizophrenia nor do they suggest the presence of gender-specific differences. CONCLUSIONS: Our data suggest that the reported genetic association by either represents type I error resulting from sampling variance or that rs175174 is in linkage disequilibrium (LD) with the functional variant for schizophrenia and different LD patterns obscure the detection of association.     

Family-based association studies of the TCP1 gene and schizophrenia in the Chinese Han population

Summary. A previous case-control study by Yang et al. indicated that the TCP1 gene in 6q25 was associated with schizophrenia in the Han population. To replicate this result, we selected eight SNPs (rs2273828, rs3818298, rs1547094, rs1547093, rs2295898, rs2295899, rs4832, rs15982) spanning the whole gene and performed a family-based study using 325 trios samples. Our transmission disequilibrium test showed neither allele nor haplotype association with schizophrenia, and suggests that the TCP1 locus is not associated with schizophrenia in the Chinese population. Since 6q25 has consistently been found to be a susceptible region for schizophrenia, we suggest that other genes within this region should be the focus of attention. The first and second authors contributed equally to this work     

Association of AKT1 with schizophrenia confirmed in a Japanese population.

BACKGROUND: Abnormality of the V-akt murine thymoma viral oncogene homologue 1 (AKT1) may be a predisposing factor in schizophrenia. Recent evidence supporting this hypothesis showed decreased AKT1 protein levels in patients with schizophrenia and significant association of AKT1 haplotypes according to the transmission disequilibrium test. METHODS: We provide the first replication of this evidence using a relatively large case-control sample (507 Japanese schizophrenia and 437 control subjects). We genotyped five single nucleotide polymorphisms (SNPs) from the original study and one additional SNP. RESULTS: We found a positive association with an SNP (SNP5) different from the original study's findings (SNP3) and also significance in the haplotypes constructed from the combination of SNP5. Linkage disequilibrium around SNP5 was complex and may produce this positive association. CONCLUSIONS: Our study provides support for the theory that AKT1 is a susceptibility gene for Japanese schizophrenia. Fine linkage disequilibrium mapping is required for a conclusive result.     

Association study of neuregulin 1 gene with schizophrenia

A number of studies have indicated that 8p22-p12 is likely to harbor schizophrenia susceptibility loci. In this region, the candidate gene of interest, neuregulin 1 (NRG1), may play a role in the pathogenesis of schizophrenia. Then in the present study, we performed the linkage disequilibrium to determine the association between three genetic variants (SNPs: rs3924999, rs2954041, SNP8NRG221533) on NRG1 gene and schizophrenia in 246 Chinese Han schizophrenic family trios using PCR-based restriction fragment length polymorphism method and denaturing high-performance liquid chromatography. The transmission disequilibrium test analysis for each variant showed a significant difference between two transmitted alleles even after Bonferroni correction (rs3924999, P=0.007752; rs2954041, P=0.0009309; SNP8NRG221533, P=0.012606). The global chi(2) test for haplotype transmission also revealed a strong association (chi(2)=46.068, df=7, P&<0.000001). Our results suggest that the NRG1 gene may play a role in conferring susceptibility to the disease.