OBJECTIVEAttention deficit hyperactivity disorder (ADHD) is one of the most common behavior disorders in childhood and adolescent. The etiology of ADHD is unknown. The aim of this study was to investigate the relationship between each of the 14 polymorphisms in the five candidate genes and ADHD, and between the combination of some polymorphisms in those genes and ADHD, in attempting to examine whether combinations of genotypes would confer a significant susceptibility to ADHD.

METHODSOne hundred and thirty-nine children with ADHD and one hundred and nineteen normal children were enrolled. Eight single nucleotide polymorphisms (SNP) of three candidate genes were examined with PCR and RFLP techniques. 48 bp VNTR in DRD4 gene was examined with PCR, nondenaturing polyacrylamide gel electrophoresis and silver staining. Five microsatellites (MS) of three candidate genes were examined with genotyping. The relationship between the combinations of 12 polymorphisms and ADHD was examined with logistic regression analysis.

RESULTS1.The frequency of 1065T/1065T genotype and the 1065T allele were significantly higher in ADHD children than that in normal controls (P<0.05). The frequency of -48G/-48G genotype of the A-48G polymorphism of DRD1 gene was significantly lower in ADHD children than that in normal controls (P<0.05). 2. A specific combination of three polymorphisms in the two genes showing an association with ADHD gave a prediction level of 77.5%.

CONCLUSIONSThe T1065G polymorphism in the SNAP-25 may be associated with ADHD. The 1065T/1065T genotype and the 1065T allele may be a risk factor for ADHD. The A-48G polymorphism of DRDI may be associated with ADHD. The -48G/-48G genotype may be a protective factor for ADHD. The specific combination of three sites of SNP in SNAP-25 gene and DRDI gene is found and shows an association with ADHD in 12 polymorphisms of the five candidate genes on glutamatergic/dopaminergic pathway.

Adolescent ; Attention Deficit Disorder with Hyperactivity ; genetics ; Child ; Female ; Humans ; Logistic Models ; Male ; Minisatellite Repeats ; Polymorphism, Single Nucleotide ; Receptors, Dopamine D3 ; genetics ; Receptors, Dopamine D4 ; genetics ; Receptors, Dopamine D5 ; genetics ; Receptors, N-Methyl-D-Aspartate ; genetics ; Synaptosomal-Associated Protein 25 ; genetics

Human personality traits have a considerable genetic component. Cloninger et al. were the first to postulate that certain personality traits, such as novelty seeking, are related to the dopamine neurotransmitter system. In this study, we investigated the associations between dopamine receptor D4 (DRD4) exon III and dopamine transporter (DAT1) polymorphisms and personality traits. The DRD4 and DAT1 gene polymorphisms were genotyped in 214 healthy Korean subjects, whose personality traits were assessed with the Temperament and Character Inventory (TCI). There were no significant differences between scores of TCI temperament dimensions (novelty seeking, harm avoidance, reward dependence, and persistence) and DRD4 gene polymorphism. The DAT1 gene polymorphisms also showed no significant association with any of the temperament subscales of the TCI. These data suggest that DRD4 and DAT1 gene polymorphism may not associated with personality traits in a Korean population.
Temperament ; Receptors, Dopamine D4/*genetics ; *Polymorphism, Genetic ; Personality/*genetics ; Male ; Korea ; Humans ; Female ; Dopamine Plasma Membrane Transport Proteins/*genetics ; Adult

The dysregulation of the dopaminergic system has been implicated in the pathophysiology of major psychosis, including schizophrenia, with dopamine receptor genes (DRDs) presently targeted as the most promising candidate genes. We investigated DRD1-5 for association with schizophrenia using a multi-stage approach in a Korean sample. One hundred forty-two SNPs in DRD1-5 were selected from the dbSNP, and the associations of each SNP were then screened and typed by MALDI-TOF mass spectrometry using pooled DNA samples from 150 patients with major psychosis and 150 controls. Each of the suggested SNPs was then genotyped and tested for an association within the individual samples comprising each pool. Finally, the positively associated SNPs were genotyped in an extended sample of 270 patients with schizophrenia and 350 controls. Among the 142 SNPs, 88 (62%) SNPs in our Korean population were polymorphic. At the pooling stage, 10 SNPs (DRD1: 2, DRD2: 3, and DRD4: 5) were identified (P < 0.05). SNPs rs1799914 of DRD1 (P = 0.046) and rs752306 of DRD4 (P = 0.017) had significantly different allele frequencies in the individually genotyped samples comprising the pool. In the final stage, with the extended sample, the suggestive association of DRD4 with rs752306 was lost, but the association of DRD1 with rs1799914 gained greater significance (P = 0.017). In these large-scale multi-stage analyses, we were able to find a possible association between DRD1 and schizophrenia. These findings suggested the potential contribution of a multi-step strategy for finding genes related to schizophrenia.
*Genetic Association Studies ; Humans ; Linkage Disequilibrium ; *Polymorphism, Single Nucleotide ; Receptors, Dopamine/*genetics ; Receptors, Dopamine D1/*genetics ; Republic of Korea ; Schizophrenia/*genetics ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

OBJECTIVETo study polymorphisms of dopamine D4 receptor (DRD4) in children with primary nocturnal enuresis (PNE) and explore the relationship between DRD4 gene polymorphisms and PNE.

METHODSGenomic DNA was isolated from leukocytes in 86 unrelated children with PNE and in 100 healthy unrelated children (controls). Polymorphisms of DRD4-1240L/S, -616C/G and -521C/T were genotyped by allele-specific primer PCR.

RESULTSThere were significant differences in allele frequencies (x2=8.13, P<0.05) and genotypes frequencies (x2=6.23, P<0.05) of DRD4-616C/G between PNE patients and healthy controls. The frequency of haplotype LCT consisting of 3 function polymorphic sites DRD4-1240L/S, -616C/G and -521C/T in PNE patients was statistically higher than that in healthy controls (x2=5.88, P<0.05).

CONCLUSIONSThe change of C to G of DRD4-616 may affect the induction and transcription of DRD4 gene. The haplotype LCT consisting of 3 function polymorphic sites DRD4-1240L/S, -616C/G and -521C/T may synergistically inhibit the transcription activity of DRD4 gene. This might lead to a reduction of DRD4 protein expression and cause nocturnal enuresis.

Adolescent ; Child ; Female ; Genotype ; Haplotypes ; Humans ; Male ; Nocturnal Enuresis ; genetics ; Polymorphism, Genetic ; Receptors, Dopamine D4 ; genetics

OBJECTIVETo investigate whether there is an association between DRD2/ANKK1 Taq IA polymorphism and early infant temperament.

METHODSDRD2/ANKK1 Taq IA polymorphism (rs1800497) was determined using polymerase chain reaction-ligase detection reaction (PCR-LDR) techniques in 149 Chinese Han infants from Changsha City. Their mothers were asked to complete the Early Infant Temperament Questionnaires (EITQ) when the infants were 1 to 4 months old (mean: 2.75 months). There were three genotypes found in these infants: C/C, T/T and C/T. The subjects were subdivided into T-carrier (CT, TT) and non-T-carrier (CC) groups for statistical analysis.

RESULTSThere were no differences in the temperament style distribution between the T-carrier and non-T carrier groups. There were also no statistically significant differences between the two groups in the score of the nine temperament dimensions.

CONCLUSIONSDRD2/ANKK1 Taq IA polymorphism is not associated with early infant temperament.

Genotype ; Humans ; Infant ; Polymorphism, Genetic ; Protein-Serine-Threonine Kinases ; genetics ; Receptors, Dopamine D2 ; genetics ; Temperament

Schizophrenia is a common but complex mental disorder affected by multiple factors. Forensic psychiatric assessment of schizophrenia involves evaluations on many aspects, but there is no effective biological identification index for schizophrenia. Researches indicate that dysfunction of dopaminergic neurotransmission plays an important role in the pathogenesis of schizophrenia. Our study reviews the classification, genetic structure of dopamine receptors and the recent pertinent studies between the dopamine receptors and schizophrenia and its forensic significance.
Forensic Medicine ; Humans ; Mental Disorders ; Polymorphism, Genetic ; Psychotic Disorders ; Receptors, Dopamine/genetics* ; Schizophrenia/genetics* ; Schizophrenic Psychology

OBJECTIVETo study the association between rs1079595 polymorphisms in the DRD2 gene and the distractibility in school-age children.

METHODSThe genotyping at rs1079595 was performed and the distractibility was measured based on the temperament questionnaire in 120 8-12 years old school-age children in order to analyze the effects of the rs1079595 polymorphism and its interaction with the gender, age and delivery mode on the distractibility.

RESULTSThere was an association between the distractibility and rs1079595 polymorphisms. The distractibility score in children with GG/GT genotypes was significantly higher than in children with the TT genotype (4.3 ± 0.6 vs 4.0 ± 0.7; P<0.05). The interaction between rs1079595 polymorphisms and the delivery mode produced an effect on the distractibility. The normal delivery children with T alleles were associated with a low distractibility (OR=0.037, P<0.01).

CONCLUSIONSThe distractibility based the temperament might be influenced by the rs1079595 polymorphism and its interaction with the delivery mode in school-age children.

Child ; Delivery, Obstetric ; Female ; Genotype ; Humans ; Logistic Models ; Male ; Polymorphism, Genetic ; Receptors, Dopamine D2 ; genetics ; Temperament

OBJECTIVETo study the effects of rs4274224 polymorphisms in the DRD2 gene, family factors and their interaction on the regularity in school-age children.

METHODSThe rs4274224 polymorphisms were genotyped using Sequenom Mass Array. The regularity was assessed based on the Middle Childhood Temperament Questionnaire (MCTQ). The parental rearing pattern was assessed with Egna Minnen av Bardnodnauppforstran (EMBU). The family function was assessed using Family Cohesion and Adaptability Scale (FACES II-CV).

RESULTSThe regularity score in children with AA genotype of rs4274224 in the DRD2 gene was significantly lower than in those with GA/GG genotype (2.9±0.6 vs 3.1±0.7; P<0.05). The results of multiple regression analysis showed that the regularity was related to child gender, father's education level and family adaptability. The results of logistic regression analysis showed that the main factors influencing the regularity were family adaptability and its interaction with rs4274224 polymorphisms. The regularity was better in children with high family adaptability than in those with low family adaptability (OR=0.112, P<0.01). The children with AA genotype and low family adaptability were tend to be associated with low regularity (OR=21.554, P<0.01).

CONCLUSIONSThe regularity based the temperament for school-age children might be influenced by family adaptability and its interaction with rs4274224 polymorphisms.

Child ; Female ; Genotype ; Humans ; Male ; Polymorphism, Genetic ; Receptors, Dopamine D2 ; genetics ; Surveys and Questionnaires ; Temperament

OBJECTIVETo investigate the mRNA expression of dopamine receptor D2 (DRD2) and dopamine transporter (DAT) in peripheral blood lymphocytes before and after treatment in children with tic disorder (TD).

METHODSRT-PCR was used to measure the mRNA expression of DRD2 and DAT in peripheral blood lymphocytes before and after treatment in 60 children with TD. The correlations between mRNA expression of DRD2 and DAT and the severity of TD were analyzed. Sixty healthy children served as the control group.

RESULTSBefore treatment, the children with TD had a significant increase in the mRNA expression of DRD2 and DAT compared with the control group (P<0.05). After 3 months of treatment with oral aripiprazole, the mRNA expression of DRD2 decreased significantly (P<0.05), while that of DAT showed no significant changes in children with TD. In the children with moderate or severe TD, the mRNA expression of DRD2 was positively correlated with Yale Global Tic Severity Scale (YGTSS) score (P<0.05). In the children with moderate TD, the mRNA expression of DAT was positively correlated with YGTSS score (P<0.05).

CONCLUSIONSIn children with TD, the mRNA expression of DRD2 in peripheral blood lymphocytes can be used as one of the indicators for diagnosing TD, assessing the severity of TD, and evaluating clinical outcomes.

Adolescent ; Child ; Child, Preschool ; Dopamine Plasma Membrane Transport Proteins ; genetics ; Female ; Humans ; Lymphocytes ; metabolism ; Male ; RNA, Messenger ; blood ; Receptors, Dopamine D2 ; genetics ; Tic Disorders ; drug therapy ; metabolism ; mortality

OBJECTIVETo assess the associations between schizophrenia and six functional genes: dopamine D2 receptor gene (DRD2), dopamine D4 receptor gene (DRD4), 5-hydroxytryptamine 2A receptor gene (5-HT2A), 5-HT6 receptor gene (5-HT6), catechol-O-methyltransferase gene (COMT) and dopamine transporter gene (DAT1).

METHODSWith the techniques of Amp-RFLP and Amp-FLP, association analysis was made between schizophrenia and the six genes in 67 schizophrenic patients from Chinese Han population.

RESULTS(1) Neither genotypes nor alleles of DRD2, 5-HT2A, 5-HT6 and COMT gene showed significant differences between patients and controls (P>0.05). (2) Six repeats (6R) in DRD4 gene, the allele of 480 bp and the genotype of 480/520 in DAT1 gene were found to be of significant differences between the two groups (P<0.05). (3) Only one negative association was observed between the 480 bp allele of DAT1 gene and schizophrenia (OR=0.441, 95% CI:0.202-0.963, Z=2.05, P<0.05).

CONCLUSIONThe 480 bp allele of DAT1 gene is negatively associated with schizophrenia in Chinese Han population, which stands for the dopamine hypothesis of schizophrenia.

Adult ; Alleles ; Catechol O-Methyltransferase ; genetics ; DNA ; genetics ; Dopamine Plasma Membrane Transport Proteins ; Female ; Gene Frequency ; Genetic Predisposition to Disease ; genetics ; Genotype ; Humans ; Male ; Membrane Glycoproteins ; Membrane Transport Proteins ; genetics ; Middle Aged ; Nerve Tissue Proteins ; Polymorphism, Restriction Fragment Length ; Receptor, Serotonin, 5-HT2A ; Receptors, Dopamine D2 ; genetics ; Receptors, Dopamine D4 ; Receptors, Serotonin ; genetics ; Schizophrenia ; genetics