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Objective: This study investigated whether the catechol-O-methyltransferase (COMT) gene V158M single-nucleotide polymorphism (SNP) influences susceptibility to tardive dyskinesia (TD). Methods: We examined 209 Korean schizophrenic patients using the Abnormal Involuntary Movement Scale (AIMS), with genotyping performed for the COMT gene V158M SNP. Results: The logistic regression analysis showed that old age [p = 0.032, OR = 1.40 (OR corresponds to 10-year), 95% CI = 1.03–1.90] was a risk factor for TD, but there was no significant association between the COMT genotype and TD. The heterozygotes (MV genotype) of the COMT gene polymorphism tended to develop TD less than homozygotes (MM and VV); however, the risk did not reach statistical significance (p = 0.050, OR = 1.81, 95% CI = 1.00–3.29). Conclusions: These results suggest that the V158M SNP of the COMT gene is not associated with TD in schizophrenia. However, there is a tendency that the heterozygous genotype of the COMT gene polymorphism has a protective effect against TD. Further investigations are warranted to evaluate a molecular heterosis of this polymorphism in development of TD in a large sample of subjects. Copyright © 2008 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Objective: The cause of restless legs syndrome (RLS) is not yet clear, but more promising theories involve dopaminergic deficiency and genetic causes. This study investigated whether single-nucleotide polymorphisms in the genes of dopamine receptors DRD1, DRD2, DRD3 and DRD4 are associated with antipsychotics-induced RLS in schizophrenia. Methods: We evaluated 190 Korean schizophrenic patients using the diagnostic criteria of the International Restless Legs Syndrome Study Group and its rating scale for RLS. Genotyping was performed for the DRD1 gene –48A/G, DRD2 gene TaqI A, DRD3 gene Ser9Gly and DRD4 gene –521C/T single-nucleotide polymorphisms. The method of multifactor dimensionality reduction was used to analyze gene-gene interactions. Results: We classified the schizophrenic patients into 96 with and 94 without RLS symptoms. The genotype frequencies of all polymorphisms investigated did not differ significantly between these 2 groups. MDR analysis did not show a significant effect of the 4 dopamine receptor gene variants on susceptibility to antipsychotic-induced RLS symptoms (p > 0.05). Conclusions: These genetics data suggest that the analyzed polymorphisms of the dopamine genes may not be associated with RLS symptoms in schizophrenia. Confirming the results reported here requires a larger-scale study involving patients taking specific antipsychotics. Copyright © 2008 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Abstract: DRD2/ANKK1 TaqI A polymorphism has been suggested to be involved in a reward-related psychiatric disorders. However, the effect of Dopamine receptor D2 (DRD2) on emotional processing has not been investigated yet. We investigated the possible relationship between DRD2/ANKK1 TaqI A polymorphism and corticostriatal response to negative facial stimuli using functional magnetic resonance imaging. All participants were genotyped with regard to the DRD2/ANKK1 TaqI A polymorphism. Our results suggest an association between the DRD2/ANKK1 TaqI A polymorphism and activations in the putamen, the anterior cingulate cortex, and amygdala in response to negative facial stimuli. Furthermore, molecular heterosis at the TaqI polymorphism of DRD2/ANKK1 may play an important role in affective regulation by corticostriatal pathway. [Copyright &y& Elsevier]

Abstract: Objective: This study examined whether the manganese superoxide dismutase (MnSOD) gene Ala–9Val single-nucleotide polymorphism (SNP) is associated with neuroleptic-induced tardive dyskinesia (TD) and the severity of the abnormal involuntary movements in Korean schizophrenic patients. Method: We investigated whether the MnSOD gene Ala–9Val SNP is associated with TD in Korean schizophrenic patients with (n =83) and without (n =126) TD who were matched for exposure to antipsychotics and other relevant variables. Results: Logistic regression analysis revealed that being older (p =0.026) was a risk factor for TD, but that there was no significant association between MnSOD gene and TD. Abnormal involuntary movements were more severe in carriers of the Ala allele than in noncarriers (p =0.044). Conclusion: These findings do not support that the MnSOD gene Ala–9Val SNP is associated with TD in Korean schizophrenic patients. However, this polymorphism might be related to the severity of abnormal involuntary movements in this population. [Copyright &y& Elsevier]

Abstract: Objective: This study investigated whether the brain-derived neurotrophic factor (BDNF) gene Val66Met single-nucleotide polymorphism (SNP) is associated with antipsychotic-induced tardive dyskinesia (TD) in schizophrenia. Methods: Genotyping was performed for the BDNF gene Val66Met SNP in Korean schizophrenic patients with (n =83) and without TD (n =126) who were matched for antipsychotic drug exposure and other relevant variables. Results: The frequencies of genotypes (χ 2 =2.37, p =0.306) and alleles (χ 2 =0.03, p =0.867) did not differ significantly between these two groups. Conclusion: These findings suggest that the BDNF polymorphism does not play a major role in the susceptibility to TD in schizophrenic patients. [Copyright &y& Elsevier]

Abstract: The personality traits associated with the noradrenergic system have not yet been clearly established. In the present study, we investigated the variable number of tandem repeats (VNTR) polymorphism of the norepinephrine transporter (NET) and monoamine oxidase A (MAOA), which are major components of the adrenergic system, to elucidate their relationship with personality. A total of 245 normal female Koreans (age 23.05±3.07 years, mean±SD) volunteered to take part in this study. They filled out a Korean version of the Temperament and Character Inventory (TCI) and were genotyped for the NET and MAOA-VNTR; the NET T-182C and MAOA-uVNTR polymorphisms were checked. We found significant main effect of NET genotype on novelty seeking (NS) score (F =5.43, p =0.021) and significant interaction between the NET and MAOA–uVNTR polymorphisms on NS score (F =11.06, p =0.001). However, there were no relationship between MAOA-uVNTR polymorphisms and NS score, and no association with other temperamental dimensions and these two polymorphisms. Our findings suggest that this functional polymorphism in the noradrenergic gene is associated with novelty seeking in Korean females. [Copyright &y& Elsevier]

Abstract: Antipsychotic-induced weight gain has important effects on treatment compliance and long-term health. Several reports have indicated that a −2548A/G single-nucleotide polymorphism (SNP) of the leptin gene is associated with antipsychotic-induced weight gain. We hypothesized that there is a similar relationship between the −2548A/G SNP and olanzapine-induced weight gain. A total of 74 Korean schizophrenic patients were examined. Their weight was measured before starting olanzapine and after long-term treatment lasting for at least 3 months. The weight gain was significantly higher for patients with the AG genotype than for those with the AA genotype (p =0.029). Analysis of covariance also showed the difference of weight gain was still significant when adjusted for sex and treatment duration (p =0.046). This finding supports the presence of a relationship between the −2548A/G SNP of the leptin gene and weight gain in Korean schizophrenic patients receiving olanzapine treatment. [Copyright &y& Elsevier]