• Anxiety and mood
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• v.2 no.1
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• pp.45-49
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• 2006

Puropse : Disturbances of dopaminergic system might be related to the possible mechanism of panic disorder. This study was aimed to examine the association of DRD2 Taq 1 polymorphism and panic disorder. Methods : One hundred and fourteen patients with panic disorder (62 male (54.4%), mean age $40.96{\pm}0.11$ years) and 200 comparison subjects (114 male (57.0%), mean age $35.57{\pm}8.81$ years)were tested for DRD2 TaqI A polymorphism. We excluded panic patients with comorbid alcohol related disorders, bipolar disorders, and any kinds of psychotic disorders because there have been some reports about association of these disease and DRD2 TaqI A polymorphism. Results : There was significant difference in the frequency of the genotype in DRD2 polymorphism between patients and controls (${\chi}^2$=6.09, df=2, p=0.048). The A1+ allele (A1A1 and A1A2) frequency analysis also showed significant association (${\chi}^2$=4.08, df=1, p=0.043). In addition, we observed a more strong and specific association between panic disorder and the A1+ allele of the DRD2 TaqI polymorphism for men (${\chi}^2$=4.71, df=1, p=0.03), but not for women (${\chi}^2$=0.45, df=1, p=0.50). Conclusion : These results in our Korean sample suggest that the DRD2 TaqI A polymorphism may be associated with panic disorder. Furthermore, we found sex-specific association of DRD2 A1 allele with panic disorder.

• Korean Journal of Biological Psychiatry
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• v.14 no.2
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• pp.106-114
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• 2007

Objective : It is suggested that disturbance of dopaminergic system might be related to the possible mechanism of social phobia. The aim of this study was to investigate the possible association of DRD2 TaqI polymorphism and social phobia. Method : Fifty-one patients with social phobia and 200 comparison subjects were tested for DRD2 TaqI A polymorphism. The severity of social phobic symptoms was measured by self-report version of the Liebowitz Social Anxiety Scale(LSAS-SR) and Hamilton anxiety scale(HAM-A). Results : There was no signigicant difference in the genotype, allele frequency, A1 carrier frequency, and heterozygote frequency DRD2 TaqI A polymorphism between the social phobia patients and the control groups. However, we found significant decrease in somatic anxiety of the HAM-A in the patients having A2A2 homozygotes(p=0.014). In addition, patients having A1A2 heterozygotes showed more anxiety in two subscales (p=0.042 in anxiety, p=0.019 in performance) of the LSAS-SR. Conclusion : These results suggest that DRD2 A2 homozygote might have a protective role against somatic anxiety, and molecular heterosis of DRD2 TaqI A polymorphism might be related with more severe anxiety in social phobia.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.12 no.2
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• pp.179-191
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• 2001

Objectives：This study evaluated the association between behavioral characteristics and polymorphisms in DAT1, DRD2, DRD3, and DRD4 genes. Methods：The subjects were 114 neonates, who were born by normal spontaneous vaginal delivery and had no physical problems. The behavioral characteristics were evaluated using Neonatal Behavioral Assessment Scale(NBAS) at $17.8{\pm}7.0$ hours after their birth to minimize environmental influences, and cord blood was used to analyze the gene polymorphisms. Results：In comparison to DAT1 gene 10/10 genotype group(N=93), other genotype group(N=19) showed significantly high NBAS scores on social-interaction, state organization, and state regulation. DRD2 gene Ser311/Cys311, TaqI A, and TaqI B polymorphisms showed no significant differences on NBAS scores when they were grouped by genotypes. DRD3 gene polymorphism and DRD4 gene promotor polymorphism showed no significant difference on NBAS scores when they were grouped by genotypes. In comparison to the short repeats(N=102), long repeats(N=10) in DRD4 gene showed significantly high habituation score of NBAS. Conclusion：These results suggest that the genetic effects of the neonatal behavioral characteristics may be mediated via DAT1 and DRD4 genes.

• Anxiety and mood
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• v.4 no.2
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• pp.142-147
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• 2008

Objective : Evidence from recent studies supports the role of genetic factors in the development of Posttraumatic Stress Disorder (PTSD). The primary aim of this study is to investigate the association between the dopamine D2 receptor (DRD2) TaqI A polymorphism and PTSD. The second aim is to examine the association between the DRD2 TaqI A polymorphism and clinical symptoms in patients with PTSD. Methods : We recruited 189 Vietnam veterans for participation in this study, among whom 99 were PTSD patients and 90 were control subjects. The presence of the DRD2 TaqI A polymorphism was determined by polymerase chain reaction (PCR). Several standardized research scales were used in the clinical assessment of PTSD, including the Combat Exposure Scale (CES), Clinician Administered PTSD Scale (CAPS), Beck Depression Inventory (BDI), and Clinical Global Impression (CGI). Results : There was no significant difference in the distribution of the DRD2 genotype, frequency and prevalence of the A1 allele, or the frequency of heterozygotes between the patients with PTSD and the controls. In the PTSD group, the patients with the A1 allele (A1A1, A1A2) scored higher on the CAPS-total (p=0.044), CAPS-avoidance symptoms (p=0.016) and BDI (p=0.024) than those without the A1 allele (A2A2). Conclusion : We could not find an association between the dopamine D2 receptor (DRD2) TaqI A polymorphism and PTSD. However, the A1 allele of DRD2 seemsto influence avoidance symptoms in patients with PTSD.

• Korean Journal of Biological Psychiatry
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• v.13 no.4
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• pp.299-304
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• 2006

Objectives : The purpose of the present study was to investigate whether the TaqI A polymorphism of dopamine receptor D2 gene(DRD2) is associated with Tourette syndrome(TS) and chronic motor tic disorder(CMT) in Korean population. Methods : DRD2 TaqI A RFLP genotyping was carried out with DNA extracted from blood samples of 75 patients with tic disorders(47 with TS and 28 with CMT) and 90 healthy subjects. Genotype and allelic frequencies for the DRD2 gene polymorphisms of the tic disorder group as a whole were compared to those of the control group. Separating the TS group, thereafter, the frequency of genotypes and alleles were compared to those of the controls. Results : The results demonstrated that genotype and allele distributions for the DRD2 gene polymorphism in the tic disorder as a whole, TS, and control groups were not significantly different. Conclusion : No association was found for DRD2 gene, TS and CMT. The data suggest that DRD2 gene may not be a useful marker for the prediction of the susceptibility of tic disorder.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.19 no.1
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• pp.19-27
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• 2008

Objectives : The aim of this study was to examine the association of attention-deficit hyperactivity disorder (ADHD) in Korean populations with functional polymorphisms of six genes dopamine receptors (Ser311/Cys311 polymorphism, Taq1 A polymorphism, and Taq1 B polymorphism in DRD2, BalI polymorphism in DRD3, and promoter -521 C/T polymorphism and exon III 48 bp repeat polymorphism in DRD4) and one gene in dopamine transporter (DAT1). Methods : Participants were 58 children with ADHD and 110 control children. The genotypes were determined by PCR. Results : There was a statistically significant difference in genotype frequency of -521 C/T polymorphism within the promoter region of the DRD4 between two groups. Furthermore, in the male group, both genotype and allele frequencies showed statistically significant differences. Conclusion : Findings of the study indicate that -521 C/T polymorphism in promoter region of DRD4 appears to be a possible candidate gene for ADHD in Korean population.

• Korean Journal of Biological Psychiatry
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• v.11 no.1
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• pp.26-32
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• 2004

Background:The dopaminergic genes have been implicated with some personality traits. Many recent studies indicated that there is a correlation between D2 dopamine receptor gene(DRD2) polymorphisms and the personality traits. The purpose of this study is to investigate a possible association between DRD2 gene (TaqI A, TaqI B) polymorphism and personality traits. Methods:The subjects were consisted of 173 blood-unrelated young female Koreans with a mean age(${\pm}SD$) of 13.88(${\pm}0.29$) years. These volunteers were recruited from one of the junior high schools in Seoul and were tested by the Korean version of the Temperament and Character Inventory(TCI). Genotyping of the DRD2 polymorphisms by PCR methods were carried out. Two DRD2 gene polymorphisms were classified and individually assessed as follows:TaqI A1+ vs A1-, TaqI B1+ vs B-. The associations between the TCI scores and TaqI A, TaqI B polymorphisms were assessed by Student's t-test. Results:In the 173 subjects, the allele frequencies of the DRD2 TaqI A1, TaqI B1 alleles ranged from 0.42 to 0.43, and these results are quite different from the ranges of 0.15-0.20 in the case of a Caucasian population. The genotype frequencies of DRD2(TaqI A1, TaqI B1) variants showed no significant deviation from the Hardy-Weinberg equilibrium. RD4(dependence vs. independence) of Cloninger's TCI, a sub-dimension of Reward Dependence, was significantly higher in the subjects having DRD2 less frequent alleles than those without these alleles. Conclusion:This study suggests that the female subjects carrying the less frequent DRD2 alleles exhibited higher reward-dependent personality trait compared to those without these alleles.

• Korean Journal of Biological Psychiatry
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• v.9 no.1
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• pp.15-24
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• 2002

Even though alcoholism is a multi-factorial psychiatric disorder, it is reasonable to suppose that genetic factors play a substantial role in the manifestation of this disorder. Because alcohol is the reinforcing substance which manifests its effects through activation of the mesolimbic dopaminergic reward pathway of the brain, the gene encoding dopamine receptor subtypes can be a major natural candidate gene. Since 1990, many association studies have identified strong evidence implicating the dopamine D2 receptor(DRD2) gene in alcoholism, specifically TaqI A minor(A1) allele. Association studies have also been conducted on other dopamine receptor(DRD3 & DRD4) polymorphisms but the results have yet to be confirmed. Through a number of other approaches, each dopamine receptor gene has been investigated in association with different phenotypes in alcoholism, but further researches will be needed. In conclusion, studies in the past decade have shown that the TaqI A1 allele of the DRD2 gene is associated with alcoholism in various subject groups. Other dopamine receptor genes have since been added to the list but yet to be identified. Thus, the knowledge of these genes and their functional significance will enhance the understanding of the underlying biological mechanisms of alcoholism. Furthermore, it could lead to more helpful prevention and treatment approaches to alcoholism.

• Korean Journal of Biological Psychiatry
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• v.13 no.3
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• pp.178-190
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• 2006

Objectives : We investigated the relationship of the alcohol withdrawal symptoms with genetic polymorphism among alcohol dependence patients. Method : The measuring instruments used in this study were the Clinical Institute Withdrawal Assessment for Alcohol(CIWA-Ar). We analyzed DRD2 TaqI A polymorphism, dopamine transporter(DAT 1) polymorphism, and catechol-O-methyltransferase(COMT) polymorphism in 108 male alcoholics and 76 healthy controls. Results : The major findings was as follows. No significant differences for genotype distribution or allele frequency were revealed comparing controls and alcoholic patients. DRD2 Taq I : The subscale score of auditory hallucination among CIWA-Ar scale in homozygote was significantly higher than in heterozygote(OR=1.34). The total score of CIWA-Ar scale in heterozygote was significantly higher than in homozygote. DAT1 : In the subject without DAT-9 gene allele, it was significantly higher of the subscale score of sweating, anxiety among CIWA-Ar scale than in the subject with DAT-9 gene allele. And The total score of CIWA-Ar scale in the subject without DAT-9 gene allele was significantly higher than in the subject with DAT-9 gene allele. COMT : The total score of CIWA-Ar scale in heterozygote was significantly higher than in homozygote. Conclusion : Our results suggest the relationship between specific genetic factors and the withdrawal symptoms of alcohol dependent patients. As the candidate gene of the severity of alcohol withdrawal syndrome, DRD2 Taq1 gene was recommended.

• Korean Journal of Biological Psychiatry
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• v.4 no.2
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• pp.225-233
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• 1997

The authors attempted to examine the allelic association between the A1 allele of Dopamine $D_2$ receptor and schizophrenia, alcoholism, drug addiction in Koreans. Schizophrenic patients(n=31), alcoholism(n=65), drug addiction(n=18) and controls(n=52) were examined by case-control study for distribution of the TaqI polymorphism of the dopamine $D_2$ receptor gene in Korean population to minimize the effect of racial differencies in gene frequencies. In schizophrenics, the numbers of schizophrenics with A1A1, A1A2, A2A2 were 9(29.0%), 15(48.4%) and 7(22.6%) respectively and in alcoholics with A1A1, A1A2, A2A2 were 14(21.5%), 36(55.4%) and 15(23.1%) respectively and in drug addiction with A1A1, A1A2, A2A2 were 2(11.1%), 10(55.6%) and 6(33.3%) respectively and in controls with A1A1, A1A2, A2A2 were 4(7.6%), 24(46.2%) and 24(46.2%) respectively. The prevalence of the A1 allele in schizophrenics, alcoholics, drug addiction and controls were 77%, 76.9%, 67% and 53.8% respectively. And the frequency of the A1 allele in schizophrenics, alcoholics, drug addiction and controls were 0.53, 0.49 0.39 and 0.31 respectively. There was significant difference in the frequency of the A1 allele between schizophrenics, alcoholics and controls. We also classified our alcoholic population. For classification by severity, we used the median MAST score 30 in our samples. There was also significant difference in the frequency of the A1 allele between less severe group(0.42) and more severe group(0.57). This data suggest that the A1 allele is associated with schizophrenia and alcoholism in Koreans. Furthermore the prevalence of the A1 allele increassed in more severely affected alcoholics. The authors conclude that our data support an allelic association between the A1 allele at dopamine $D_2$ receptor and schizophrenia, alcoholism. These results suggest the A1 allele of the $DRD_2$ gene is associated with a number of behavior disorders in which it may act as a modifying gene rather than as the primary etiological agent.