• Korean Journal of Biological Psychiatry
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• v.9 no.1
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• pp.25-33
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• 2002

Serotonin transporter(5-HTT) is one of the major action site of antidepressants in neuronal cells. According to the recent studies, it is known that the functional polymorphism in the promoter region of the 5-HTT gene(5-HTT linked polymorphism repetitive element in promoter region, 5-HTTLPR) is associated with antidepressant responsiveness, and the distributions of 5-HTTLPR is various among the different populations. Our preliminary study suggested that it is possible to measure the endophenotype of 5-HTTLPR genotype by examining the pharmacodynamic research of the 5-HTT in platelet membranes. However, there are limitations to predicting the antidepressant responsiveness only from the endophenotypic characteristics of 5-HTT gene promoter polymorphism, and therefore we propose to use the pharmacogenomic methods for overcoming these limitations. We found that the significant correlations existed among the genetic polymorphisms of biogenic amine transporters whose structure and characteristics are similar to the 5-HTT, and the predictable odds ratio of antidepressant responsiveness are increased significantly by combining the effect with other associated polymorphisms, compared to the effect of 5-HTT promoter polymorphism only. These results support the hypothesis that antidepressant treatment has to be individualized according to the genetic and ethnic background of depressed patients. It would be possible to develope the evaluation tools to predict the antidepressant responsiveness and its side effect profile, if scientists reveal the genes related to the action mechanism as well as the metabolism of antidepressants so as to discover the interaction of those genes and contribution of endogenotypes toward antidepressant responsiveness.

• Korean Journal of Biological Psychiatry
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• v.10 no.2
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• pp.159-167
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• 2003

Objective:Under the hypothesis that 5-HTTLPR polymorphism plays some role in the susceptibility or vulnerability of some subgroup of alcohol dependence, associations of 5-HTTLPR polymorphism with alcohol dependence were examined. Method:This association analysis included 109 Korean alcohol dependent and 113 Korean control subjects. DNA of all subjects were genotyped for the biallelic functional polymorphism in the 5-HTTLPR. Considering the likelihood of heterogeneity in the alcohol dependence phenotype, alcohol dependent subjects were subgrouped by onset age, family history of alcohol dependence and severity of withdrawal symptoms. Results:There were no significant differences in the frequencies of either the 5-HTTLPR genotype or the short vs. long allele in alcohol dependent and control subjects. The frequency of the S allele and S-carrier (LS or SS genotype) was significantly increased in the early onset alcohol dependent subjects and the familial alcohol dependent subjects compared with that in the control subjects. Conclusion:The results suggest that the 5-HTT 'S' promoter polymorphism is associated with an increased susceptibility or vulnerability to develop early onset alcohol dependence and familial alcohol dependence, which characterize Cloninger's type 2 alcohol dependence.

• Korean Journal of Biological Psychiatry
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• v.13 no.3
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• pp.170-177
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• 2006

Objectives : Disturbances of serotonergic system might be related to the possible mechanism of social phobia. This study was to investigate the association of serotonin transporter gene and social phobia. Methods : Sixty nine patients with social phobia(51 male(73.9%), mean age $35.17{\pm}11.89$ years) and seventy four normal controls(54 male(73.0%), mean age $33.46{\pm}9.63$ years) were tested for serotonin transporter gene-linked polymorphic region(5-HTTLPR) polymorphism. Additionally, patients were grouped into 46 generalized(GEN) and 23 nongeneralized(NGEN) subgroups and 5-HTTLPR polymorphism was compared with that of normal controls. The genotypes and allele frequencies of the 5-HTTLPR polymorphism between social phobia and the control group were compared. Genomic DNA was extracted from their blood and 5-HTTLPR polymorphisms were determined by using polymerase chain reaction. Results : Significant association was observed between the S(ss) genotype and social phobia, by functional classification(p=.010). In allele frequency analysis, a significant association was also observed between the short allele and social phobia(p=.030). A significant associations between S genotype and each subgroup were observed(GEN p=.045 ; NGEN p=.033), but there were no differences in allele frequency. And, no differences in genotype and allele distribution between two subgroups were found. Conclusion : The results in our Korean sample suggest that S genotype of 5-HTTLPR may be associated with social phobia and s allele may be an important genetic factor that activates social phobic symptoms. But, further studies including large number of samples are necessary to elucidate these present findings.

• Korean Journal of Biological Psychiatry
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• v.8 no.2
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• pp.220-225
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• 2001

As numbers of serotonin's function are so many, studies of serotonin are numerous nowadays. In the beginning, concentration of metabolites such as 5-HIAA was a key issue, but recent studies have been challenged for serotonin receptor genes and their relation to mood disoder. Serotonin transporter(5-HTT) gene is a strong candidate gene of mood disoder for following reason. Serotonin transporter is a key protein in the serotonin pathway as it regulate the concentration of serotonin in the synaptic clept and essential pathophysiology of depression is dysregulation of 5-HTT so that all antidepressants have effect of 5-HTT antagonist. The decrease of 5-HTT in the platelet and in brain of the depressive patients is much consistent results in the studies of the pathophysiology of mood disorder till now. By this, we will be able to develop simple and easy marker for diagnosis, type, and treatment monitoring of depression. Many psychiatrists have sought the independent genes in relation to depression or schizophrenia. Obviously, the hereditary vulnerability contributes to etiology of mood disorders, but it is difficult to discriminate the independent genes because of many environmental factors. Moreover, in the hereditarily complex diseases such as mood disorder, the only vulnerability of gene can not sufficiently explain the etiology. In the future, to exclude the role of the gene-environmental interaction, the methods such as gene transfer can be considered. In the opposite direction, by using the gene destruction method, the role of target genes can be examined. As yet the concept of the gene expression, neural plasticity, neurogenesis and etc, is the elementary stage. The development of this field will help to establish the treatment strategy of chronic and refractory mood disorders.

• Korean Journal of Biological Psychiatry
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• v.19 no.2
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• pp.106-113
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• 2012

Objectives : The purpose of this study is to investigate the relationship between the triallelic serotonin transporter gene and stressful life events to determine their effect on depression with alcohol dependence. Methods : Ninety-five hospitalized patients with alcohol dependence (73 male, 22 female) were enrolled in this study. Thirty-two (33.7%) of the total patients were diagnosed with major depressive disorder and dysthymic disorder by Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders-IV. The characteristics of stress were evaluated using the stressful life events scale, and depressive symptoms were assessed using the depression scale (Beck Depression Inventory, BDI). Alcoholism with depression (n = 32) and alcoholism without depression (n = 63) were genotyped for the triallelic serotonin transporter gene ($L_A$ : higher expressing allele, $L_G$/S : lower expressing allele). Results : There was no significant difference in the allele frequency between the depression group and the non-depression group (${\chi}^2$ = 0.345, p = 0.619). $L_G$/S alleles had more comorbid depression in the higher score of stressful life events scale [Mental-Haenszel (MH)-${\chi}^2$ = 4.477, p = 0.034]. But there was no significant difference in the comorbidity according to the scores from the stressful life event scale in the $L_A$ alleles (MH-${\chi}^2$ = 0.741, p = 0.399). In the results, alcohol-dependent individuals with $L_G$/S alleles had more comorbid depression than those with $L_A$ alleles when they had experienced severe stressful life events (MH-odds ratio = 2.699, p = 0.028). Conclusions : These results suggest that there is no direct relationship between triallelic serotonin transporter gene and depression in the alcohol dependent patients. But alcohol dependent individuals with the lower expressing alleles of the serotonin transporter gene were more susceptible to depression than those with the higher expressing alleles in response to stressful life events.

• Korean Journal of Psychosomatic Medicine
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• v.16 no.1
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• pp.47-51
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• 2008

Objectives : The aim of this study was to investigate the relationship between the norepinephrine(NET) transporter T-182C polymorphism and anxiety-related traits in Korean adolescent females. Methods : One hundred sixty-nine Korean adolescent females were tested for the NET T-182C polymorphism by PCR based methods; anxiety-related traits were evaluated using the anxiety sensitivity index(ASI) and the trait form of the Spielberg State-Trait Anxiety inventory(STAI-T). Results : Scores of anxiety related traits were not different between genotypes. Comparison between T allele carries and non carriers revealed no significant difference. Conclusion : These findings suggest that the NET T-182C polymorphism is not associated with anxiety-related traits in Korean female adolescents.

• Korean Journal of Biological Psychiatry
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• v.16 no.1
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• pp.25-36
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• 2009

Objectives : The aim of this study was to investigate the association between Korean ADHD patients and the l/s polymorphism of serotonin transporter(5-HTTLPR). Methods : The study sample consisted of 189 Korean ADHD children diagnosed by Kiddie-Schedule for Affective Disorders and Schizophrenia-Present and Lifetime Version-Korean Version(K-SADS-PL), both parents of ADHD children, and 150 normal children. DNA were extracted from the blood of all samples, and genotyping was done. Based on the allele and genotype information, not only the case-control analysis between ADHD and normal children but also the family-based association test among ADHD children and their parents. Transmission disequilibrium test(TDT) were performed for family-based associated test(number of trio=113). The results of the clinical rating and neuropsychological tests were compared according to the l/s genotype of ADHD children. Results : In case-control analysis, there were no statistically significant difference of l/s gene polymorphism between ADHD and normal children in various kinds of analysis condition. In family-based association study, TDT failed to detect linkage disequilibrium between l/s gene polymorphism and ADHD in whole ADHD families. However, in the families of ADHD inattentive type only(number of trio=23), I allele was transmitted more preferentially in the proband with ADHD even if the number of families was small(${\chi}^2$=4.57, p=.032). In the analysis of the results from the clinical scales and neuropsychological tests in ADHD children, the score of the Novelty- Seeking of ADHD children with l/l genotype was significantly lower than with the other genotypes(F=3.15, p=.047), and that of Self Transcendence was significantly higher(F=4.25, p=.017). Conclusion : The results of this study suggest there were no significant genetic association between the 5- HTTLPR gene polymorphism and Korean ADHD.

• Korean Journal of Biological Psychiatry
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• v.25 no.3
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• pp.79-87
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• 2018

Objectives Internet gaming disorder (IGD) is known to be related to stress and the serotonin-transporter-linked polymorphic region (5-HTTLPR) that is known to be associated with stress and has been studied to affect various psychiatric illness outbreaks. We tried to examine the relationship between stress, 5-HTTLPR and IGD. Methods A total of 59 participants with IGD, diagnosed according to the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria and 67 normal controls (NC) were enrolled. The IGD group and the NC were compared using chisquare test and independent sample t-test, and logistic regression analysis was used to examine the relationship between stress, the 5-HTTLPR, and IGD. Results The mean scores for anxiety, impulsivity and stress were significantly higher in the IGD group than in the NC. In addition, there was a significant association between stress and IGD [odds ratio (OR) = 1.172, 95% confidence interval (CI) = 1.008-1.362]. Conclusions This study showed that stress would affect IGD. Therefore, the evaluation and management of stress should be included in the diagnosis and treatment of IGD.

• Korean Journal of Biological Psychiatry
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• v.11 no.1
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• pp.49-53
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• 2004

Objective:A Comparison of QTc prolongation for various antipsychotics and an analysis of QTc prolongation for the various types of serotonin transporter polymorphism were performed. Method:EKG was checked, followed by QTc measurement as Bazett's correction, and the serotonin transporter polymorphism was examined in 110 chronic schizophrenia patients were performed EKG before 24 weeks ago. We defiened QTc prolongation as over 450ms. The risk factor of sudden cardiac death were defiend as QTc prolongation and or 60ms in delta value. Result:The prevalence of QTc prolongation in this study was 7.3%, and the prevalence of over 60ms was 4.5%. Patients who had the risk factors were 10(9.1%). 6/52 who prescribed atypical antipsychotics and 2/58 who prescribed haloperidol showed QTc prolongation. The prevalence who had the risk factor of sudden cardiac death were 16% in atypical antipsychotics group, 3.4% in haloperidol group. QTc prolongation were observed more frequently in l/l type than s/s type. l allele frequency were 50% in QTc prolongated group, 19% in not prolongated group. l allele had an association with QTc prolongation(p<0.01). Conclusion:The prevalence of QTc prolongatin was frequent in chronic schizophrenia patients who were prescribed atypical antipsychotics. It has strong association with l allele of 5-HTTLPR.