情感性精神障碍与5-羟色胺转运体基因的连锁不平衡研究

目的探讨情感性精神障碍与5-羟色胺转运体(5-HTT)基因之间的分子遗传学联系：方法以中国汉族人群中的72个情感性精神障碍核心家系(双相情感性精神障碍56例，重性抑郁症34例)作为研究对象，采用自编家系调查表、美国精神障碍诊断与统计手册第4版诊断标准并结合心理测评工具，应用聚合酶链反应(PCR)和限制性片段长度多态性分析方法，检测其5-HTT基因启动子区(5-HTTLPR)、第2内含子[数目可变的顺向重复(VNTR)]和3’端非编码区(3’UTRG／T)基因多态性，并进行连锁不平衡(TDT)分析。结果5-HTT基因中的VNTR与3’UTRG／T2个位点组合单体型与情感性精神障碍存在关联(TDT-x^2=4．08，经Monte Carlo逼真法1000次重复校正后的经验P值=0．04)，其他各位点5-HTTLPR、VNTR、3’UTRG／T等位基因与情感障碍未发现存在连锁不平衡，其他位点组合的单体型分析也未发现存在连锁不平衡。结论5-HTT基因在情感性精神障碍的遗传病因中可能起着一定作用。     

5-羟色胺转运体基因多态性与儿童孤独症核心家系的关联研究

目的 探讨中国汉族人群5-羟色胺转运体基因多态性(5-HTTLPR)与儿童孤独症的关系。方法 应用聚合酶链式反应技术(PER),测定了82个儿童孤独症核心家系患儿及其父母的基因型和等位基因。结果 传递不平衡检验(TDT)显示等位基因传递无统计学意义(X2=0.014,P>0.05)。结论 5-HTTLPR与儿童孤独症没有关联,5一羟色胺转运体基因可能在儿童孤独症发病中不起主要作用。     

青少年抑郁症5-羟色胺转运体基因多态性与疗效的相关研究

目的 在汉族抑郁症青少年中探索5-羟色胺转运体(5-HTT)基因多态与5-羟色胺再摄取抑制剂(SSRIs)疗效的关系.方法 研究对象为来自上海市精神卫生中心门诊及病房、符合美国精神障碍诊断与统计手册第四版(DSM-Ⅳ)抑郁症诊断标准、且接受SSRIs治疗的青少年抑郁症患者,平均年龄(15.9±1.7)岁,共有76例患者入组,脱落11例;于入组时和SSRIs治疗第2、4、6周末分别进行17项汉密尔顿抑郁量表(HAMD17)、汉密尔顿焦虑量表(HAMA)评定.应用PCR及PCR-RFLP技术对入组患者进行5-HTTLPR、5-HTT3'UTR多态基因分型.结果 SSRIs治疗有效组患者和无效组患者在5-HTTLPR多态及5-HTT3'UTR多态的基因型频率分布无明显差异(χ2=0.12,P=0.94;χ2=0.91,P=0.63)、等位基因频率分布也无明显差异(χ2=0.03,P=0.88;χ2=0.73,P=0.43).结论 在中国汉族青少年抑郁症患者群中5-HTTLPR、5-HTT3'UTR多态可能与SSRIs抗抑郁疗效之间无明显关联.     

5-羟色胺转运体启动子区域基因多态性位点与双相障碍的关联研究

目的:探讨5-羟色胺转运体蛋白基因启动子区域(5-HTTLPR)位点多态性与双相障碍之间的遗传学联系。方法:以中国西北地区汉族人群中51例双相障碍患者(患者组)的核心家系(父母组102名)共153人为研究对象;取每个成员血液样本DNA,应用聚合酶链反应技术扩增5-HTTLPR位点,以琼脂糖凝胶电泳法进行基因分型,对5-HTTLPR位点多态性与双相障碍之间分子遗传学联系进行以家系为基础的连锁不平衡分析。结果:无论5-HTTLPR位点各种基因型(L/L、L/LG、S/L、S/S、S/LG)还是等位基因(L、LG、S)频率在患者组和父母组比较差异无统计学意义(χ2=3.732,P0.05;χ2=0.633,P0.05)。基于基因型的单倍体相对风险分析(GHRR)以及传递不平衡分析(TDT)也未发现5-HTTLPR与双相障碍存在连锁不平衡(GHRR:P0.05;TDT:χ2=2.418,P0.05)。结论:5-HTTLPR多态性位点在中国西北地区汉族人群双相障碍发病机制中不起主要作用,但不能排除微效作用的存在。     

多巴胺D4受体基因多态性与注意缺陷多动障碍的关联分析

目的探讨注意缺陷多动障碍(ADHD)与多巴胺D4受体(DRD4)基因第3外显子48bp可变数目顺向重复(VNTR)多态性的关系.方法对176例ADHD患儿(病例组)、98个ADHD核心家系(家系组,共294人)及119名正常对照(对照组)进行ADHD与DRD4基因48bpVNTR多态性的关联分析.结果所测人群中的48bpVNTR多态性表现为2～6次重复(分别为407、bp、455bp、503bp、551bp及599bp);其中以4次重复(73.9%)和2次重复(21.8%)最为常见;尚未发现7次重复序列.病例组2/2基因型(6.3%)显著低于对照组(14.3%;P=0.02),这种差异主要表现在ADHD混合型.对98个家系的精确多等位基因不平衡传递检验,未发现等位基因与ADHD存在连锁不平衡(x2=5.119,v=4,P＞0.05).结论DRD4基因48bpVNTR多态性主要集中于4次重复序列片段上;48bp片段的重复次数可能与ADHD相关,重复2次时可以减少ADHD的易患性.     

汉族核心家系中强迫症与儿茶酚胺氧位甲基转移酶和单胺氧化酶基因多态性的关联分析

目的 分析儿茶酚胺氧位甲基转移酶(catechol-O-methyltransferase,COMT)基因和单胺氧化酶(monoamine oxidases A, MAOA)基因T941G多态位点与汉族强迫症的关联.方法 应用特异性引物序列聚合酶链反应检测134个强迫症核心家系(患者及其生物学父母)的COMT基因val158met和MAOA基因T941G多态性.采用单体型相对危险度分析(haplotype relative risk,HRR)及传递不平衡检验(transmission disequilibrium test, TDT)进行关联分析.结果 112个和103个核心家系分别进入COMT基因和MAOA基因的TDT和HRR分析.TDT检测McNemar检验(P=0.15)及HRR检测( χ 2=3.58, P=0.06)均不支持COMT val158met多态位点存在传递不平衡; MAOA基因T941G位点的TDT( χ 2=4.78, P=0.04)及HRR分析显示存在传递不平衡( χ 2=7.63, P＜0.01),等位基因T较多地传给下一代(57.22%).结论 本研究提示MAOA基因T941G多态性在汉族人种中可能与强迫症关联,不支持COMT基因val158met多态性与强迫症关联.     

早发性精神分裂症核心家系的亚甲基四氢叶酸还原酶基因传递不平衡研究

目的:在中国汉族早发性精神分裂症家系中探讨亚甲基四氢叶酸还原酶(MTHFR)基因与精神分裂症的相关性。方法:采用聚合酶链反应-限制性片段长度多态性方法(PCR-RFLP)技术,检验111个早发性精神分裂症核心家系MTHFR基因A1298C和C677T多态性,并进行连锁不平衡检验(LD)以及传递不平衡检验(TDT)。结果:A1298C及C677T等位基因在父母与先证者间传递差异均无统计学意义(χ2=0.216,P=0.642;χ2=0.143;P=0.706);连锁不平衡检验表明A1298C与C677T之间存在中度连锁不平衡(D'=0.529);单体型TDT显示早发性精神分裂症核心家系中各单体型传递差异均无统计学意义(P>0.05)。结论:MTHFR基因A1298C及C677T多态性与早发性精神分裂症无明显关联。     

5-羟色胺转运体基因多态性与自杀未遂的关联研究

目的探讨5-羟色胺转运体(5-HTT)基因启动子区多态性(5-HTTLPR)与自杀未遂的关系。方法运用聚合酶链反应技术(PCR)检测71例自杀未遂患者和80名健康对照5-HTTLPR基因型。结果自杀未遂组与对照组5-HTTLPR的基因型及等位基因(S/L)频率差异无统计学意义(P>0.05);进一步分析显示,有精神疾病自杀未遂组(37例)的短重复序列S等位基因频率为85.1%,与正常对照组(72.5%)及无精神疾病自杀未遂组(69.1%)的差异均具有统计学意义(X2=4.49,P=0.04;X2=5.21,P=0.03)。结论5-HTTLPR的S等位基因和精神病自杀未遂存在关联。     

伴与不伴学习困难的注意缺陷多动障碍患儿认知特点的比较

目的　探讨伴与不伴学习困难 (LD)注意缺陷多动障碍 (ADHD)患儿认知特点的异同。方法　运用韦氏儿童智力量表 (C WISC)、韦氏记忆量表、数字划消测验、Stroop测验和瑞文标准推理测验 ,对 66例仅患ADHD患儿 (ADHD组 )和 2 9例合并LD的ADHD患儿 (ADHD +LD组 )的智力、记忆力、注意力及执行功能进行比较。结果　 (1 )ADHD组的平均年龄 [(9 5± 2 0 )岁 ]小于ADHD +LD组[(1 1 3± 2 3)岁 ] ,差异有显著性 (P <0 0 5) ;(2 )ADHD组在C WISC中仅注意 /不分心因子分 [(1 0 2±1 3)分 ]高于ADHD +LD组 [(96± 1 3)分 ] ,差异有显著性 (P =0 0 2 8) ,其余各项测验结果两组间的差异均无显著性 (P >0 0 5)。结论　ADHD +LD组注意 /不分心因子受损更严重 ,其余认知模式与ADHD组相似。     

不同发病年龄强迫症患者6种功能基因的分子遗传学研究

目的探讨与5-羟色胺和多巴胺递质系统有关的基因在强迫症发病中的作用。方法收集120个强迫症的核心家系,按患者的发病年龄分为≤16岁组和>16岁组,应用基因扩增的限制性片段长度多态和数目可变的顺向重复多态技术对强迫症核心家系在5-羟色胺2A受体基因、5-羟色胺转运体(5-HTT)基因、多巴胺D2受体(DRD2)基因、多巴胺D4受体(DRD4)基因、儿茶酚氧位甲基转移酶(C0MT)基因、单胺氧化酶A(MAO-A)基因等6个基因的7个位点进行传递不平衡检测和数量性状的传递不平衡检测以及DRD4基因的单体型分析。结果 (1)未发现6个功能基因与强迫症存在传递不平衡;(2)DRIY2-141C Del／Ins多态性与≤16岁组存在传递不平衡(X2=3.98,P=0.04),COMT-Val／Met多态性与>16岁组存在传递不平衡(X2=3.65,P=0.05),经相关分析,这两个位点与强迫症的发病年龄相关(DRD2:r=-0.29,P=0.002;COMT:r=-0.19,P=0.04)。结论DRD2基因和COMT基因可能与不同发病年龄的强迫症病因相关。     

Serotonin transporter gene polymorphisms and hyperserotonemia in autistic disorder.

Previous studies have provided conflicting evidence regarding the association of the serotonin transporter (5-HTT) gene with autism. Two polymorphisms have been identified in the human 5-HTT gene, a VNTR in intron 2 and a functional deletion/insertion in the promoter region (5-HTTLPR) with short and long variants. Positive associations of the 5-HTTLPR polymorphism with autism have been reported by two family-based studies, but one found preferential transmission of the short allele and the other of the long allele. Two subsequent studies failed to find evidence of transmission disequilibrium at the 5-HTTLPR locus. These conflicting results could be due to heterogeneity of clinical samples with regard to serotonin (5-HT) blood levels, which have been found to be elevated in some autistic subjects. Thus, we examined the association of the 5-HTTLPR and VNTR polymorphisms of the 5-HTT gene with autism, and we investigated the relationship between 5-HTT variants and whole-blood 5-HT. The transmission/disequilibrium test (TDT) revealed no linkage disequilibrium at either loci in a sample of 96 families comprising 43 trios and 53 sib pairs. Furthermore, no significant relationship between 5-HT blood levels and 5-HTT gene polymorphisms was found. Our results suggest that the 5-HTT gene is unlikely to play a major role as a susceptibility factor in autism.     

Serotonin transporter gene and autism: a haplotype analysis in an Irish autistic population

The role of the serotonin transporter (5-HTT) in the development of neuropsychiatric disorders has been widely investigated. Two polymorphisms, an insertion/deletion in the promoter region and a 12 repeat allele in a variable nucleotide tandem repeat (VNTR) in intron 2, drive higher expression of the 5-HTT gene. Four studies have shown nominally significant excess transmission of alleles of the 5-HTT gene in autism, while three studies have reported no excess transmission. This present study investigates the role of 5-HTT in the genetically homogenous Irish population. In all, 84 families were genotyped for five polymorphisms (three SNPs, a VNTR and an in/del). The analysis of allele transmissions using the transmission disequilibrium test (TDT) was undertaken and indicated preferential transmission of the short promoter allele (TDT P-value=0.0334). Linkage disequilibrium between markers was calculated and haplotypes were assessed for excess transmission and odds ratios (ORs) to affected children. A number of haplotypes, especially those involving and surrounding SNP10, showed evidence of association. The ORs ranged from 1.2 to 2.4. The most significant haplotype associated with transmission to affected probands was the SNP10-VNTR-SNP18 haplotype (chi(2)=7.3023, P=0.0069, odds ratio=1.8). This haplotype included the 12 repeat allele of the VNTR, which is associated with increased expression and may play a subtle role in the early development of the brain in affected probands.     

Evidence that variation at the serotonin transporter gene influences susceptibility to attention deficit hyperactivity disorder (ADHD): analysis and pooled analysis

Reduced central serotonergic activity has been implicated in poor impulse regulation and aggressive behaviour in animals, adults and also young children.(1,2) Two recently published studies have implicated variation at a polymorphism in the promoter of the serotonin transporter (5HTT; hSERT) in influencing susceptibility to ADHD.(3,4) Consistent with these results we have also found a trend for the long allele of the promoter polymorphism to influence susceptibility to ADHD in a sample of 113 ADHD parent proband trios (65 transmissions vs 49 non-transmissions, chi(2) = 2.25, P = 0.13). A pooled analysis of our, and these published results demonstrated a significant over representation of the long allele of the promoter in ADHD probands compared to controls (chi(2) = 7.14, P = 0.008). We have also examined two other 5HTT polymorphisms (the VNTR in intron 2 and the 3' UTR SNP). TDT analysis demonstrated preferential transmission of the T allele of the 3' UTR SNP (chi(2) = 4.06, P = 0.04). In addition, ETDT analysis of haplotypes demonstrated significant preferential transmission of haplotypes containing the T allele of the 3' UTR SNP with the long allele of the promoter polymorphism (chi(2) = 13.18, 3 df, P = 0.004) and the 10 repeat of the VNTR (chi(2) = 8.77, 3 df, P = 0.03). This study provides further evidence for the possible involvement of the serotonin transporter in susceptibility to ADHD.     

Significance of serotonin transporter gene 5-HTTLPR and variable number of tandem repeat polymorphism in attention deficit hyperactivity disorder

The purpose of this study was to evaluate the relationship between attention deficit hyperactivity disorder (ADHD) and polymorphism of the two regions of the 5-HTT gene [variable number of tandem repeats (VNTR) and 5-HTTLRR] in a sample of Turkish children. Using the PCR technique, these polymorphisms were assessed in 71 patients with ADHD and 128 healthy controls. The 5-HTTLPR S/S genotype was significantly lower in the patients than in the controls (p = 0.018). Homozygous and heterozygous L variant predominated in the ADHD group. But the VNTR STin2.12/12 genotype was significantly less found in the patients than in the controls (p = 0.001). There was no significant difference between the frequency of the short (S), long, 10, and 12 alleles of both groups. The lack of an S/S variant of 5-HTTLPR polymorphism of the STin2.12/12 variant of VNTR polymorphism appears to be associated with an increased risk of ADHD.     

Population-based and family-based studies on the serotonin transporter gene polymorphisms and bipolar disorder: a systematic review and meta-analysis

The serotonin transporter (5-HTT) is a candidate gene for bipolar disorder (BPD). It has been investigated for association with the illness in a series of studies, but overall results have been inconsistent and its role in the disorder remains controversial. Systematic reviews using meta-analytical techniques are a useful method for objectively and reproducibly assessing individual studies and generating combined results. We performed two meta-analyses of published studies--both population-based and family-based studies--investigating the association between BPD and the 5-HTT gene-linked polymorphic region (5-HTTLPR) and the intron 2 variable numbers of tandem repeats (VNTR) polymorphisms. The literature was searched using Medline and Embase to identify studies for inclusion. We statistically joined population-based and family-based studies into a single meta-analysis. For both polymorphisms, our review revealed significant pooled odds ratios (ORs): 1.12 (95% CI 1.03-1.21) for the 5-HTTLPR and 1.12 (95% CI 1.02-1.22) for the intron 2 VNTR. Meta-regression showed that neither the study type (population-based vs family-based; P=0.41 for the 5-HTTLPR and P=0.91 for the intron 2 VNTR) nor the sample ethnicity (Caucasian vs non-Caucasian; P=0.35 for the 5-HTTLPR and P=0.66 for the intron 2 VNTR) significantly contributed to the heterogeneity of the meta-analyses. The observed ORs could be regarded simply as a very small but detectable effect of the 5-HTT, which has an additive effect when combined with other susceptibility loci. Alternative hypotheses on this finding were also discussed: a stronger effect of the haplotypes involving the two polymorphisms or other SNP markers; a more direct effect of these polymorphisms on specific phenotypes of BPD; and the presence of gene-environment interaction as a mediator of the genetic effects of 5-HTT.     

Serotonin transporter promoter variants: Analysis in Indian autistic and control population

Serotonin transporter (5-HTT) is a transmembrane protein belonging to Na+/Cl- dependent membrane transporter family and transports 5-HT across the membranes of presynaptic neurons. 5-HTT-linked polymorphic region (5-HTTLPR) gained much interest because of the differential regulation of expression and activity of 5-HTT by its various genotypes. A population-based study has been conducted on 5-HTTLPR with 358 individuals, which included 79 autistic probands, 136 parents, and 143 controls from two subpopulations of east and northeast regions of India. The genotypic frequencies of all the groups conform to Hardy-Weinberg equilibrium. With the finding of efficacy of serotonin reuptake inhibitors in ameliorating ritualistic behavior in autistic disorder, 5-HTT emerged as a putative candidate gene for autism and association studies have been carried out in different ethnic populations. But these studies were inconclusive due to conflicting results on association. Because such a study has never been performed in the Indian population, we have tested the possible involvement of 5-HTTLPR polymorphism with autism. The present study failed to establish any association or linkage of 5-HTTLPR with autism in the Indian population by case-control studies (chi2 = 1.314, P = 0.63) and family-based approaches (TDT chi2 = 0.22, P = 0.64 and HHRR-chi2 = 0.25, P = 0.61). However, when a meta-analysis of all the available TDT data, inclusive of the present study is carried out, we observed a significant preferential transmission of S-allele from parents to the affected offspring (chi2 = 7.51, P = 0.006) indicating an association of 5-HTTLPR with autism.     

Association between obsessive-compulsive disorder and a variable number of tandem repeats polymorphism in intron 2 of the serotonin transporter gene

BACKGROUND: Pharmacological studies indicate a dysregulation of the serotonergic system in obsessive-compulsive disorder (OCD). A variable number tandem repeats (VNTR) polymorphism with three alleles (Stin2.9, Stin2.10, Stin2.12) has been described in intron 2 of the serotonin transporter (5-HTT) gene. This polymorphism has been associated with unipolar depression, bipolar disorder, schizophrenia, and anxiety disorders including OCD. METHODS: The association between OCD and the polymorphism is examined in 97 OCD patients, 578 psychiatric controls and 406 healthy controls, all Spanish Caucasians. RESULTS: Genotype frequencies for the polymorphism were significantly different in OCD patients, psychiatric patients and controls. There was a significant excess of 12/12 and 12/10 genotypes in OCD patients compared to psychiatric patients and controls. CONCLUSIONS: Our results indicate a possible association between the Stin2.12 allele of the VNTR polymorphism and OCD.     

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。