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TaqI-A polymorphism linked to the DRD2 gene and P300 in alcoholic patients
Jiménez-Arriero,M.A.; Ponce,G.; Rodríguez-Jiménez,R.; Aragués,M.; Galvan,A.; Rubio,G.; Hoenicka,J.; Palomo,T.;
The European Journal of Psychiatry , 2006, DOI: 10.4321/S0213-61632006000100005
Abstract: background and objectives: different studies carried out mainly in young non-consuming children of alcoholics show an association of p300 abnormalities with alcoholism and with the taqi-a1 allele. since the relationship between p300 and the taqi-a1 allele has not been specifically studied in alcoholic patients, our objective was to investigate whether the association exits in this population. methods: our sample consisted of 176 recently detoxified male alcohol-dependent patients. these patients had been alcohol dependent from a mean age of 22.6 years and consumed on average 164.63 (± 142.99) cm3 of alcohol daily. p300 was studied using an auditory paradigm. taqi-a polymorphism genotyping was performed. the association between p300 and taqi-a, and correlation with age and alcohol consumption, was studied. results: the taqi-a1 allele was found in 38.6% of our patients (n = 68). the latency and amplitude of p300 were 361.64 milliseconds and 17.53 microvolts, respectively. p300 wave latency in alcoholic patients was longer than the reference value obtained from a sample of healthy men of the event-related potentials unit (p < 0.001). alcoholic patients who carried the taqi-a1 allele showed more prolonged p300 latency than non-carriers, and these in turn more than the control subjects. p300 characteristics varied according to age, but an association with amount of alcohol or number of years consuming was not found. conclusions: there is a relationship between the taqi-a polymorphism and p300 wave characteristics in alcoholic patients. further investigations need to be carried out in non-consuming alcoholic patients and in healthy control subjects to confirm this association and to clarify the possible influence of the neurotoxic effects of alcohol on p300 physiology.
TaqI-A polymorphism linked to the DRD2 gene and P300 in alcoholic patients  [cached]
M.A. Jiménez-Arriero,G. Ponce,R. Rodríguez-Jiménez,M. Aragués
The European Journal of Psychiatry , 2006,
Abstract: BACKGROUND AND OBJECTIVES: Different studies carried out mainly in young non-consuming children of alcoholics show an association of P300 abnormalities with alcoholism and with the TaqI-A1 allele. Since the relationship between P300 and the TaqI-A1 allele has not been specifically studied in alcoholic patients, our objective was to investigate whether the association exits in this population. METHODS: Our sample consisted of 176 recently detoxified male alcohol-dependent patients. These patients had been alcohol dependent from a mean age of 22.6 years and consumed on average 164.63 (± 142.99) cm3 of alcohol daily. P300 was studied using an auditory paradigm. TaqI-A polymorphism genotyping was performed. The association between P300 and TaqI-A, and correlation with age and alcohol consumption, was studied. RESULTS: The TaqI-A1 allele was found in 38.6% of our patients (n = 68). The latency and amplitude of P300 were 361.64 milliseconds and 17.53 microvolts, respectively. P300 wave latency in alcoholic patients was longer than the reference value obtained from a sample of healthy men of the Event-Related Potentials Unit (p < 0.001). Alcoholic patients who carried the TaqI-A1 allele showed more prolonged P300 latency than non-carriers, and these in turn more than the control subjects. P300 characteristics varied according to age, but an association with amount of alcohol or number of years consuming was not found. CONCLUSIONS: There is a relationship between the TaqI-A polymorphism and P300 wave characteristics in alcoholic patients. Further investigations need to be carried out in non-consuming alcoholic patients and in healthy control subjects to confirm this association and to clarify the possible influence of the neurotoxic effects of alcohol on P300 physiology.
Examining impulsivity as an endophenotype using a behavioral approach: a DRD2 TaqI A and DRD4 48-bp VNTR association study
Dan TA Eisenberg, James MacKillop, Meera Modi, Joshua Beauchemin, David Dang, Stephen A Lisman, J Koji Lum, David S Wilson
Behavioral and Brain Functions , 2007, DOI: 10.1186/1744-9081-3-2
Abstract: 195 individuals (42% male) were recruited from a university campus and were assessed in small group sessions using personal computers. Genotyping was conducted using previously established protocols. For the DRD2 TaqI A locus, individuals were designated as possessing at least one copy of the A1 allele (A1+) or not (A1-), and for the DRD4 48-bp VNTR locus, individuals were designated as having at least one long allele (7 repeats or longer, L+) or not (L-). Principal analyses used multiple univariate factorial 2 (A1+/A1-) × 2 (L+/L-) analyses of variance.A significant main effect of A1+ status on DDT performance was evident (p = .006) as well as a significant interaction effect (p = .006) between both genes. No other significant effects were evident on the self-report measures, with the exception of a trend toward an interaction effect on the Sensation Seeking Scale. Exploratory analyses suggested that the significant effects were not a function of population stratification or gender.These data suggest that the DRD2 TaqI A and DRD4 VNTR polymorphisms influence impulsivity as measured with a delay discounting task. Specifically, these findings suggest that an interaction between the functional effects of the two unlinked genotypes results in significant difference in the balance of mesolimbic dopaminergic activation relative to frontal-parietal activation. However, these findings are also the first in this area and must be replicated.These findings suggest a meaningful interaction between the DRD2 TaqI A and DRD4 VNTR polymorphisms in the expression of impulsivity and provide initial support for the utility of using behavioral measures for clarifying genetic influences on impulsivity.The effort to characterize the behavioral effects of genetic polymorphisms has produced a massive web of ambiguous associations and linkages [1-3]. One strategy to clarify the genetic bases of behavior is the endophenotype approach [2,4,5], which seeks to elucidate genetic associations wi
Association between the DRD2-141C Insertion/Deletion polymorphism and schizophrenia
Cordeiro, Quirino;Siqueira-Roberto, Jacqueline;Zung, Stevin;Vallada, Homero;
Arquivos de Neuro-Psiquiatria , 2009, DOI: 10.1590/S0004-282X2009000200004
Abstract: epidemiological studies have demonstrated that the genetic component is an important risk factor for the development of schizophrenia. the genes that codify the different compounds of the dopaminergic system have created interest for molecular investigations in patients with schizophrenia because the antipsychotic drugs, especially those of first generation, act on this cerebral system. thus the aim of the present study was to investigate the possible association between the -141 ins/del (rs1799732) polymorphism of the dopamine receptor type 2 (drd2) and schizophrenia. the distribution of the alleles and genotypes of the studied polymorphism was investigated in a sample of 229 patients and 733 controls. there were statistical differences in the allelic (χ2=9.78; p=0.001) and genotypic genotypic (χ2=12.74; p=0.001) distributions between patients and controls. thus the -141c ins/del polymorphism of the drd2 gene (allele ins) was associated to the scz phenotype in the investigated sample.
Multivariate Analysis of Dopaminergic Gene Variants as Risk Factors of Heroin Dependence  [PDF]
Andrea Vereczkei, Zsolt Demetrovics, Anna Szekely, Peter Sarkozy, Peter Antal, Agnes Szilagyi, Maria Sasvari-Szekely, Csaba Barta
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0066592
Abstract: Background Heroin dependence is a debilitating psychiatric disorder with complex inheritance. Since the dopaminergic system has a key role in rewarding mechanism of the brain, which is directly or indirectly targeted by most drugs of abuse, we focus on the effects and interactions among dopaminergic gene variants. Objective To study the potential association between allelic variants of dopamine D2 receptor (DRD2), ANKK1 (ankyrin repeat and kinase domain containing 1), dopamine D4 receptor (DRD4), catechol-O-methyl transferase (COMT) and dopamine transporter (SLC6A3) genes and heroin dependence in Hungarian patients. Methods 303 heroin dependent subjects and 555 healthy controls were genotyped for 7 single nucleotide polymorphisms (SNPs) rs4680 of the COMT gene; rs1079597 and rs1800498 of the DRD2 gene; rs1800497 of the ANKK1 gene; rs1800955, rs936462 and rs747302 of the DRD4 gene. Four variable number of tandem repeats (VNTRs) were also genotyped: 120 bp duplication and 48 bp VNTR in exon 3 of DRD4 and 40 bp VNTR and intron 8 VNTR of SLC6A3. We also perform a multivariate analysis of associations using Bayesian networks in Bayesian multilevel analysis (BN-BMLA). Findings and conclusions In single marker analysis the TaqIA (rs1800497) and TaqIB (rs1079597) variants were associated with heroin dependence. Moreover, –521 C/T SNP (rs1800955) of the DRD4 gene showed nominal association with a possible protective effect of the C allele. After applying the Bonferroni correction TaqIB was still significant suggesting that the minor (A) allele of the TaqIB SNP is a risk component in the genetic background of heroin dependence. The findings of the additional multiple marker analysis are consistent with the results of the single marker analysis, but this method was able to reveal an indirect effect of a promoter polymorphism (rs936462) of the DRD4 gene and this effect is mediated through the –521 C/T (rs1800955) polymorphism in the promoter.
Haplotype frequencies at the DRD2 locus in populations of the East European Plain
Olga V Flegontova, Andrey V Khrunin, Olga I Lylova, Larisa A Tarskaia, Victor A Spitsyn, Alexey I Mikulich, Svetlana A Limborska
BMC Genetics , 2009, DOI: 10.1186/1471-2156-10-62
Abstract: We investigated TaqI B, BclI, MboI, TaqI D, and TaqI A RFLPs in 17 contemporary populations of the East European Plain and Siberia. Most of these populations belong to the Indo-European or Uralic language families. We identified three common haplotypes, which occurred in more than 90% of chromosomes investigated. The frequencies of the haplotypes differed according to linguistic and geographical affiliation.Populations in the northwestern (Byelorussians from Mjadel'), northern (Russians from Mezen' and Oshevensk), and eastern (Russians from Puchezh) parts of the East European Plain had relatively high frequencies of haplotype B2-D2-A2, which may reflect admixture with Uralic-speaking populations that inhabited all of these regions in the Early Middle Ages.The DRD2 gene is located on chromosome 11 and encodes the neuronal dopamine receptor D2, which plays a role in movement, emotional memory, and appetitive behavior [1]. The DRD2 locus was an object of numerous genetic association studies [2-5], and the most extensively studied polymorphism is a TaqI A RFLP (rs1800497; in the vicinity of the DRD2 gene), which has been associated with the pathology of psychoses (schizophrenia and manic-depressive disorder), Parkinson's disease, and various substance abuse syndromes. It has been proposed that TaqI A might be in linkage disequilibrium with some unidentified polymorphisms within the exons or regulatory regions of the DRD2 gene, but recently it has been mapped to the last exon of the ANKK1 (ankyrin repeat and kinase domain containing 1) gene, and it results in a Glu-Lys substitution [6]. Other frequently studied RFLPs, for example, TaqI B and D (rs1079597 and rs1800498, respectively) are located in the introns of the DRD2 gene and, most probably, have no functional significance.TaqI B, TaqI D, and TaqI A polymorphisms have also been studied on a worldwide scale [[7-11]; the ALFRED database, http://alfred.med.yale.edu/alfred/index.asp webcite], and centers of dispersal, wh
P300 in alcohol dependence: Effects of TaqI-A genotype
Jiménez-Arriero,M.A.; Rodríguez-Torresano,J.; Ponce,G.; Hoenicka,J.; Rodríguez,R.; Rubio,G.; Palomo,T.;
The European Journal of Psychiatry , 2009, DOI: 10.4321/S0213-61632009000400003
Abstract: background and objectives: taqi-a polymorphism, related to d2 dopamine receptor (drd2), and event-related p300 potentials have been considered markers of alcohol dependence. the effect of alcohol use variables and taqi-a on p300 in a single sample have been hardly analysed previously. this study examined changes in p300 parameters after six months of abstinence in alcohol-dependent subjects classified by their taqi-a genotype. methods: 102 men with alcohol dependence were studied at baseline and at 6 months of continued abstinence. p300 was recorded using an auditory paradigm. taqi-a polymorphism was genotyped: 34.3% of sample was classified as a1[taqi-a1/taqi-a1and taqi-a1/taqi-a2] and 65.7% as a2 [taqi-a2/taqi-a2]. the association between p300 and taqi-a and the correlation with age and alcohol consumption were considered. results: the abstinence period was not associated to differences in neither p300 latency (f[1, 99] = 1.154 p = 0.285) nor amplitude (f[1, 99] = 1.453, p = 0.231). a1 subgroup was related to a longer latency (f[1, 99] = 5.055 p = 0.027), an early abuse age onset (f[1, 100] = 14.552 p <0.001) and close to be significant to an early dependence age onset (f[1, 100] = 3.868 p = 0.052). other drinking pattern variables were not associated to p300 measures. family history for alcoholism and taqi-a were not related (x[1] = 0.327 p = 0.568) and no association was found with p300 measures. current age correlated positively with p300 latency (f[1, 99] = 26.082, p <0,001) and negatively with amplitude (f[1, 99] = 5.297 p = 0.023). p300 amplitude was not influenced by alcohol use variables nor taqi-a polymorphism. conclusions: p300 latency could be a biological marker of vulnerability to alcohol dependence related to taqi-a1 polymorphism, irrespective of alcohol use variables.
P300 in alcohol dependence: Effects of TaqI-A genotype  [cached]
M.A. Jiménez-Arriero,J. Rodríguez-Torresano,G. Ponce,J. Hoenicka
The European Journal of Psychiatry , 2009,
Abstract: Background and Objectives: TaqI-A polymorphism, related to D2 dopamine receptor (DRD2), and event-related P300 potentials have been considered markers of alcohol dependence. The effect of alcohol use variables and TaqI-A on P300 in a single sample have been hardly analysed previously. This study examined changes in P300 parameters after six months of abstinence in alcohol-dependent subjects classified by their TaqI-A genotype. Methods: 102 men with alcohol dependence were studied at baseline and at 6 months of continued abstinence. P300 was recorded using an auditory paradigm. TaqI-A polymorphism was genotyped: 34.3% of sample was classified as A1[TaqI-A1/TaqI-A1and TaqI-A1/TaqI-A2] and 65.7% as A2 [TaqI-A2/TaqI-A2]. The association between P300 and TaqI-A and the correlation with age and alcohol consumption were considered. Results: The abstinence period was not associated to differences in neither P300 latency (F[1, 99] = 1.154 p = 0.285) nor amplitude (F[1, 99] = 1.453, p = 0.231). A1 subgroup was related to a longer latency (F[1, 99] = 5.055 p = 0.027), an early abuse age onset (F[1, 100] = 14.552 p <0.001) and close to be significant to an early dependence age onset (F[1, 100] = 3.868 p = 0.052). Other drinking pattern variables were not associated to p300 measures. Family history for alcoholism and TaqI-A were not related (X[1] = 0.327 p = 0.568) and no association was found with p300 measures. Current age correlated positively with P300 latency (F[1, 99] = 26.082, p <0,001) and negatively with amplitude (F[1, 99] = 5.297 p = 0.023). P300 amplitude was not influenced by alcohol use variables nor TaqI-A polymorphism. Conclusions: P300 latency could be a biological marker of vulnerability to alcohol dependence related to TaqI-A1 polymorphism, irrespective of alcohol use variables.
Haplotype diversity and linkage disequilibrium at the DRD2 locus among the tribes of western and southern regions of India  [cached]
Aggarwal Aastha,Gauniyal Mansi,Pattanayak Ipsa,Kshatriya Gautam
Indian Journal of Human Genetics , 2010,
Abstract: Background: Dopamine receptor D2 (DRD2) is an important gene having functional significance in the fields of neuropsychiatry and pharmacology and also has importance in evolutionary studies. Materials and Methods: This study was undertaken to find out the haplotype distribution and linkage disequilibrium (LD) pattern for the three TaqI sites (TaqI ′A′, TaqI ′B′ and TaqI ′D′) in the DRD2 gene in 232 unrelated individuals from five ethno-linguistically distinct endogamous tribal populations; Siddis and Gonds of Uttara Kannada district, Karnataka; Varli and Kolgha of Valsad district, Gujarat; and Dangi Konkana of Dang district, Gujarat. The genotype data obtained after molecular analysis of the three DRD2 sites was subjected to statistical analysis such as calculation of allele frequencies, haplotype frequencies among others. Subsequently, a neighbor-joining tree was also constructed from the data obtained. Results: The three DRD2 sites were found to be polymorphic in all the populations. All the populations showed high levels of heterozygosities. Out of the eight possible haplotypes, most populations shared seven haplotypes. Of all the populations, Siddis showed the highest frequency of the ancestral haplotype B2D2A1 (11.4%). Significant LD was found to exist for TaqI ′A′ and TaqI ′B′ sites in both the populations. Conclusion: The findings are in concurrence with those from other Indian studies, especially from Dravidian-speaking South Indian populations. Similar pattern of diversity observed for ethnically and linguistically diverse populations in the present study is indicative of complex structure of Indian populations.
A Family-Based Association Study of Attention-Deficit Hyperactivity Disorder and Dopamine D2 Receptor TaqI A Alleles.  [PDF]
Yu-Shu Huang,Shih-Ku Lin,Yu-Yu Wu,Chia-Chen Chao
Chang Gung Medical Journal , 2003,
Abstract: Background: Over the past 5 years, considerable progress has been made in the identificationof polymorphic variation within monoamine system genes that are associatedwith the attention-deficit hyperactivity disorder (ADHD) phenotype.In this study, we investigated the association of the dopamine D2 receptor(DAD2) TaqI A and ADHD in a Taiwanese sample.Methods: The sample consisted of 98 children with ADHD and 154 of their parents.ADHD cases were ascertained from the Child Psychiatric Clinics at ChangGung Memorial Hospital in the Taipei area, Taiwan. A diagnosis of ADHDwas made following clinical interviews plus completion of a standard maternalinterview and Conner's revised rating scales by a parent and teacher.Association of DRD2 TaqI A polymorphism in this sample was investigatedusing a haplotype-based haplotype relative-risk method.Results: Among our subjects, there was no significant difference in transmission ratesbetween DRD2 TaqI A1 and A2 alleles.Conclusion: The results of this study do not support DRD2 playing a major role inTaiwanese children with ADHD.
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