• Journal of the Korean Chemical Society
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• v.50 no.2
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• pp.123-128
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• 2006

Behcet's disease (BD) is a systemic vasculitis characterized by recurrent oral and genital ulcers, and ocular inflammation, and which may involve the joints, skin, central nervous system and gastrointestinal tract. Although the exact pathogenesis for BD is not completely understood, it has been suggested that the disease is triggered in genetically susceptible individuals by environmental factors, such as microbial agents. It is noted that multiple genes, including MHC (major histocompatibility complex) and non-MHC genes, are implicated in the pathogenesis of BD. This study tries to determine whether IL-6 gene polymorphisms are associated with susceptibility to Behcet's disease in Koreans. Gene polymorphisms were typed by VNTR (variable number of tandem repeat), RFLP (restriction fragment length polymorphism), DHPLC (denaturing high performance liquid chromatography).There were no evidences for genetic association conferred by the IL-6prom polymorphism. However, significant differences in the IL-6vntr genotype and allele frequencies were found between patients with BD and controls. The IL-6vntr*C allele appeared to be an additional susceptibility gene to Korean BD. Further studies in other populations and gene are required to confirm these results.

• Sleep Medicine and Psychophysiology
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• v.15 no.1
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• pp.39-43
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• 2008

Objectives: The pathophysiology of restless legs syndrome (RLS) is not obvious, but many promising theories involve dopaminergic deficiency and genetic causes. The RLS is presumed to occur more frequently among schizophrenic patients who take antipsychotics, most of which blocks the dopamine receptors. This study aimed to investigate whether dopamine transporter gene (DAT1) 40 base pair (bp) variable number of tandem repeat (VNTR) polymorphism is associated with the antipsychotic-induced RLS in schizophrenia. Methods: We determined the diagnosis of RLS among the 190 Korean schizophrenic patients by the diagnostic criteria of the International Restless Legs Syndrome Study Group (IRLSSG). Genotyping was performed for the 40bp VNTR in DAT1 gene using polymerase chain reaction. Results: We separated the schizophrenic patients into 44 patients with RLS and 146 patients without RLS. The genotype and allele frequencies did not differ significantly between two groups. Conclusions: These results suggest that DAT1 gene 40bp VNTR is not associated with the antipsychotic-induced RLS in schizophrenia. To confirm these results, larger-scale association study is needed in the future.

• Sleep Medicine and Psychophysiology
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• v.18 no.1
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• pp.35-39
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• 2011

Objective: Diurnal preference is an attribute reflecting whether people are alert and preferring to be active either early or late in the day. It also referred to as chronotype or morningness-eveningness trait. The PER3 genes have been known to influence diurnal preference. In this study, we have investigated the associations between the PER3 gene polymorphisms and diurnal preference in a healthy young population, controlling for the social and environmental confounding factors. Methods: The participants in this experiment included 299 unrelated medical college students (M=191, F=108), with a mean age of 22.9 years. Diurnal preference was measured by a single administration of the 13-item Composite Scale for Morningness (CSM). Genotyping of the PER3 VNTR (rs57875989) was performed using polymerase chain reaction. A two-tailed alpha of 0.05 was chosen. Results: The mean${\pm}$SD score on the CSM scale for all subjects was 31.90${\pm}$6.39. There was no significant difference in total CSM score between gender groups, although females showed a trend towards higher morningness score. Although PER3 5R/5R showed the tendency towards high CSM scores, there were no significant differences on CSM scores among genotypes and allele status of PER3 VNTR (rs57875989). Conclusions: We could not confirm that the PER3 VNTR is associated with diurnal preference in a Korean healthy young population. The future studies need to investigate the association between diurnal preference and other polymorphisms of PER3 gene in larger sample of Korean young healthy population.

• Korean Journal of Biological Psychiatry
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• v.8 no.2
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• pp.239-245
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• 2001

Objective : Dopamine transporter is member of family of Na/Cl dependent neurotransmitter transporter, 12 transmembrane domain, that has high substrate specificity, affinity. It is related with dopamine reuptake in presynaptic vesicle. DAT has a VNTR in its 3'-untranslated region(UTR). 3'-UTR VNTR polymorphism is related with modification of dopamine transmission. The association between with VNTR polymorphism and neuropsychiatric disorders such as alcohol dependence, and low activity ALDH has been studied, but their relationship is unclear. We study about association of 3'-UTR VNTR of DAT gene and G2319A and alcohol dependence. Method : Group of Korean subjects were studied with alcohol dependence(n=49 male) compared to mentally healthy controls(n=53 male). The peripheral blood sample was acquired, and Polymerase Chain Reaction(PCR) amplification, MspI procedure was done. Result : There was a significant difference between alcohol dependence group and normal control(genotype frequency p<0.05, allele frequency p<0.05) Allele A frequency and genotype(GG, GA) frequency was a significant difference between alcohol dependence group and normal control(p<0.05). Conclusion : Our study showed that genetic polymorphism of DAT1 G2319A had relation with alcohol dependence.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.18 no.2
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• pp.154-161
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• 2007

Objectives: The aim of the current study is to test for the association of DRD4 exon III VNTR polymorphism with attention-deficit hyperactivity disorder(ADHD) in Korean children population. Methods: 113 Korean children with ADHD, 102 parents, and 133 control subjects participated with the current study. The distribution of genotypes and alleles of DRD4 exon III VNTR in children with ADHD was compared with that in control subjects. In addition, 69 children with ADHD and their parents were analyzed using the transmission disequilibrium test(TDT). Results: We could not find any significant differences in the distribution of genotypes and alleles at DRD4 exon III VNTR polymorphism between children with ADHD and control subjects. In addition, there was no preferential transmission of long allele of DRD4 exon III VNTR polymorphism. Conclusion: These results suggest that DRD4 is not associated with ADHD in Korean children population.

• Korean Journal of Biological Psychiatry
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• v.6 no.2
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• pp.170-175
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• 1999

Until recently, the etiology of schizophrenia was generally attributed to abnormalities in dopaminergic neurotransmission. Specifically, an excess of dopaminergic activity in the mesolimbic system has been postulated to produce the positive symptoms, while decreased dopaminergic activity in the mesocortical system has been suggested to cause negative symptoms. Accordingly, we performed an association study of schizophrenia with TH gene. Three hundred and seventy four biologically unrelated schizophrenic patients meeting DSM-III-R criteria from Kangnam St. Mary's Hospital affiliated with Catholic university of Korea were recruited for our study. The 393 healthy controls were volunteers for DNA library of Kangnam St. Mary's Hospital without personal or family history of psychiatric and neurologic illness. DNA was extracted from peripheral mononuclear cells and polymorphic region was amplified by polymerase chain reaction. TH intron 1 VNTR polymorphism was typed by silver staining. The allele distributions of TH gene were not different between schizophrenics and controls. However, the frequency of allele A was significantly higher in positive group than that of negative group of schizophrenics. These findings suggest that poitive schizophrenia may be associated with allele A of TH gene.

• Korean Journal of Biological Psychiatry
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• v.9 no.1
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• pp.8-14
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• 2002

Patients with attention deficit hyperactivity disorder(ADHD) have symptoms of inattention, hyperactivity, impulsivity. Symptoms of ADHD are responsive to medications such as methylphenidate, dextroamphetamine, pemoline, and bupropion. The functional change of the dopamine transporter is related to the therapeutic effect of these drugs. This can be one reason for the dopamine transporter to be emphasized in the research field of ADHD. ADHD has a genetic tendency. Since dopamine transporter gene(DAT1) knock out mice were reported to be several times more active than normal mice in a novel situation, lights has been shed on DAT1 as a candidate gene for ADHD. Though there have been several studies which reported an association between DAT1 and ADHD, the association between DAT1 and ADHD is not conclusive. Since Vandenbergh reported the DAT1 polymorphism with variable number of tandem repeats(VNTR), and the racial differences in allelic frequencies of the DAT1, wide ethnic variation in the distribution of the DAT1 polymorphism had been confirmed. Wide ethnic variation in the distribution of the DAT1 suggested that there might be ethnic difference in the association between DAT1 and ADHD. Before applying previous findings to Koreans, verification might be needed for Korean patients with ADHD.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.16 no.2
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• pp.199-210
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• 2005

Objective : Attention deficit hyperactivity disorder(ADHD) affects $5-10\%$ of children in Korea, with more boys and girls being diagnosed. Despite seriousness of ADHD, little is known about its causes. From the current genetic epidemiologic studies, ADHD is known as a heritable disorder. Till now, however, there have been very few genetic studies about ADHD in Korea. The aim of the this study is to examine the association between dopamine transporter gone type 1 and ADHD using case-control design in Korean ADHD probands and normal controls. Materials and Method : Child Psychiatric Genetic research team in Seoul National University Hospital, Clinical Research Institute recruited the ADHD probands using clinical interview/observation, diverse rating scales, and neuropsychological tests. For eliminating phenocopy or ADHD, diagnosis of ADHD was based upon clinical data, psychometric data, and parent/teacher reports. Total 85 ADHD-probands were recruited as final study subjects and independent 100 normal adults participated in this study as control group. For all the ADHD probands, and controls, the 3'-UTR-VNTR polymorphism of DAT1 was analyzed. Based on the DAT1 allele and genotype informations, Chi-square test based on case-control design was performed. Results : As for genetic study, total of 85 probands and 100 controls were included for the genetic analysis. Four different alleles, 350bp (7repeat), 440bp (9repeat), 480bp (10repeat) and 520bp (11repeat) were found in DAT1 gene of study subjects. In case-control analysis, ADHD probands and parents have significantly more 9 repeat allele and 9/10 genotype. Also, The probands with 9repeat allele have more commission errors in ADS. Conclusion : The positive association between ADHD and DAT1 gene was replicated in this report like other previous results for caucasian children and Korean children with ADHD. There are ongoing studies on other candidate genes such as DRD4 and DRD5 and it would be required to explore the association of these candidate genes in Korean children with ADHD. These ongoing genetic research will contribute to the understanding of heterogenous genetic and environmental etiologies of ADHD phenotype, which will lead to the development of more comprehensive treatment and preventive interventions for ADHD.

• Korean Journal of Biological Psychiatry
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• v.14 no.1
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• pp.55-60
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• 2007

Objectives : There have been many association studies of panic disorder. However, studies about the dopaminergic function in panic disorder have been few. This study was aimed to examine the possible association of dopamine transporter gene(DAT1) polymorphism and panic disorder in Korean population. Methods : Ninety-eight patients with panic disorder(43 male(46.9%), mean age $42.13{\pm}10.88$ years) and one hundred and thirteen comparison subjects(67 male(40.7%), mean age $33.14{\pm}8.55$ years) were tested for DAT1 polymorphism. Genotypes of DAT1 with variable number of tandem repeats(VNTR) were determined using polymerase chain reaction. The differences of allelic frequency and genotype frequency distribution between patient and the control group were tested with Fisher-Freeman-Halton test. Results : There was association between DAT1 polymorphism and panic disorder(allele : p<0.03, genotype : p<0.05). The frequency of 10/10 homozygotes of DAT1 was significantly higher in control group(${\chi}^2$=4.452, df=1, p=0.035). Conclusion : These results in our Korean samples suggest that DAT1 polymorphism might be associated with the vulnerability of panic disorder. Possible association of dopaminergic genes and panic disorder should be investigated with future studies using larger and different population.

• Korean Journal of Biological Psychiatry
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• v.11 no.2
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• pp.165-172
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• 2004

Objective:Although polymorphism of dopamine transporter gene(DAT1) has been considered to be implicated in the pathogenesis of social phobia, previous investigations have been inconsistent and controversial. The authors investigated the relationship between DAT1 polymorphism and social phobia in Koreans. Methods:DAT1 and alleles of fifty subjects who met DSM-IV criterion of social phobia, and those of age- & sex- matched fifty normal controls in Korea were compared. Additionally, patients were grouped into generalized(33) and nongeneralized(17) types and DAT1 polymorphism was compared with that of age- & sex- matched controls. DAT1 with variable number of tandem repeats(VNTR) were determined by using polymerase chain reaction. To compare the distribution of the DAT1 polymorphism between different groups, Fisher's exact test was used. Results:There were no significant differences in either genotypic(p=0.451) or allelic(p=0.452) distributions between the social phobia patients and the controls. There also were no differences in genotypic distribution between subtypes of social phobia patients and the controls. Conclusion:We couldn't find any association between DAT1 polymorphism and social phobia. Further studies including larger number of samples and diverse clinical variables should be conducted to elucidate the present findings.