Association of BDNF, HTR2A, TPH1, SLC6A4, and COMT polymorphisms with tDCS and escitalopram efficacy: ancillary analysis of a double-blind, placebo-controlled trial

Objective: We investigated whether single nucleotide polymorphisms (SNPs) associated with neuroplasticity and activity of monoamine neurotransmitters, such as the brain-derived neurotrophic factor (BDNF, rs6265), the serotonin transporter (SLC6A4, rs25531), the tryptophan hydroxylase 1 (TPH1, rs1800532), the 5-hydroxytryptamine receptor 2A (HTR2A, rs6311, rs6313, rs7997012), and the catechol-O-methyltransferase (COMT, rs4680) genes, are associated with efficacy of transcranial direct current stimulation (tDCS) in major depression. Methods: Data from the Escitalopram vs. Electrical Current Therapy for Treating Depression Clinical Study (ELECT-TDCS) were used. Participants were antidepressant-free at baseline and presented with an acute, moderate-to-severe unipolar depressive episode. They were randomized to receive escitalopram/tDCS-sham (n=75), tDCS/placebo-pill (n=75), or placebo-pill/sham-tDCS (n=45). General linear models assessed the interaction between treatment group and allele-wise carriers. Additional analyses were performed for each group and each genotype separately. Results: Pairwise group comparisons (tDCS vs. placebo, tDCS vs. escitalopram, and escitalopram vs. placebo) did not identify alleles associated with depression improvement. In addition, exploratory analyses also did not identify any SNP unequivocally associated with improvement of depression in any treatment group. Conclusion: Larger, combined datasets are necessary to identify candidate genes for tDCS response.

Source, metabolism and function of dopamine in digestive tract / 生理学报

Dopamine (DA), as a catecholamine neurotransmitter widely distributed in the central nervous system and the peripheral tissues, has attracted a lot of attention. Especially in recent years, DA has been found to regulate the function of the immune system, and the involvement of DA in the intestinal mucosal inflammation-related diseases has become a hot research topic. The digestive tract is an important source of peripheral DA, and DA is not only produced in the enteric nervous system and gastrointestinal epithelium, but also produced by intestinal microorganisms. In addition to the synthetases of DA, the DA contents in body tissues are also affected by the two kinds of metabolic enzymes, monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT). This article reviewed the sources, metabolism, and functions of DA in digestive tract, especially focusing on the distribution and function of MAO and COMT, the enzymes degrading DA.

Biological Aspects of Aggression and Violence in Schizophrenia

Although the majority of patients with schizophrenia are not actually violent, an increased tendency toward violent behaviors is known to be associated with schizophrenia. There are several factors to consider when identifying the subgroup of patients with schizophrenia who may commit violent or aggressive acts. Comorbidity with substance abuse is the most important clinical indicator of increased aggressive behaviors and crime rates in patients with schizophrenia. Genetic studies have proposed that polymorphisms in the promoter region of the serotonin transporter gene and in the catechol-O-methyltransferase gene are related to aggression. Neuroimaging studies have suggested that fronto-limbic dysfunction may be related to aggression or violence. By identifying specific risk factors, a more efficient treatment plan to prevent violent behavior in schizophrenia will be possible. Management of comorbid substance use disorder may help prevent violent events and overall aggression. Currently, clozapine may be the only effective antipsychotic medication to repress aggressive behavior. With the current medical field moving toward tailored medicine, it is important to identify vulnerable schizophrenia populations and provide efficient treatment.

Postpartum depression: association with genetic polymorphisms of noradrenaline metabolic enzymes and the risk factors / 南方医科大学学报

OBJECTIVE@#To investigate the association of genetic polymorphisms of norepinephrine metabolizing enzymes with postpartum depression and analyze the risk factors for postpartum depression in women following cesarean section.@*METHODS@#A total of 591 Chinese woman of Han Nationality undergoing caesarean section were enrolled in this study. The diagnosis of postpartum depression was established for an Edinburgh Postnatal Depression Scale (EPDS) score ≥9. For all the women without antepartum depression, the genotypes of catechol-O-methyltransferase (COMT; at 5 sites including rs2020917 and rs737865) and monoamine oxidase A (rs6323) were determined using Sequenom Mass Array single nucleotide polymorphism (SNP) analysis. We analyzed the contribution of the genetic factors (SNPs, linkage disequilibrium and haplotype) to postpartum depression and performed logistic regression analysis to identify all the potential risk factors for postpartum depression and define the interactions between the genetic and environmental factors.@*RESULTS@#The incidence of postpartum depression was 18.1% in this cohort. Univariate analysis suggested that COMT polymorphism at rs2020917 (TT genotype) and rs737865 (GG genotype) were significantly correlated with the occurrence of postpartum depression ( < 0.05). Logistic regression analysis showed that COMT polymorphism at rs2020917 (TT genotype) and rs737865 (GG genotype), severe stress during pregnancy, and domestic violence were the risk factors for postpartum depression ( < 0.05); no obvious interaction was found between the genetic polymorphisms and the environmental factors in the occurrence of postpartum depression.@*CONCLUSIONS@#The rs2020917TT and rs737865GG genotypes of COMT, stress in pregnancy, and domestic violence are the risk factors for postpartum depression.

Pharmacological Treatment in Parkinson's Disease

Parkinson's disease is one of the most common neurodegenerative disorders world widely. Although curable therapies are practically not available yet, symptomatic managements using anti-Parkinson medications have shown to be quite effective to improve patients' quality of life. The discovery of dopaminergic deficits in Parkinson's disease in 1960s have brought about the human clinical trials of levodopa, which opened an “Era of Dopamine” in treatment history of the Parkinson's disease. Levodopa still remains gold standard. Dopamine agonists have proved their efficacies and delayed the development of long-term complications of levodopa use. Inhibitors of respective enzyme monoamine oxidase-B and catechol-O-methyltransferase, anticholinergics, and amantadine strengthen the therapeutic effects via either monotherapy or adjunctive way. Strategy of continuous dopaminergic stimulation and disease modification are weighing in current advances. This article is providing evidence-based review of pharmacological treatment of Parkinson's disease from early to advanced stages as well as management its unavoidable adverse reactions.

Catechol-O-methyltransferase (COMT) polymorphisms modulate working memory in individuals with schizophrenia and healthy controls

Objective: Cognitive impairment is a core feature of schizophrenia, related to dopaminergic dysfunction in the prefrontal cortex (PFC). It is hypothesized that functional single nucleotide polymorphism (SNP) rs4680 of the catechol-O-methyltransferase (COMT) gene could mediate the relationship between cognition and dopamine activity in the PFC. Other COMT SNPs could also play a role. Methods: We evaluated the role of three COMT SNPs (rs737865, rs165599, and rs4680) in schizophrenia and their impact on three working memory tasks. For genetic association analyses, 212 individuals with schizophrenia and 257 healthy controls (HCs) were selected. The Visual Working Memory (VWM) Task, Keep Track Task, and Letter Memory Task were administered to 133 schizophrenics and 93 HCs. Results: We found a significant association of rs737865, with the GG genotype exerting a protective effect and the GA haplotype (rs4680/rs165599) exerting a risk effect for schizophrenia. COMT rs4680 AA carriers and rs737865 AA carriers scored lowest on the Keep Track Task. When the genotype*group interaction effect was evaluated, rs165599 exerted opposite effects for VWM and Keep Track task performance in patients and controls, with AA carriers scoring lowest on both tests among controls, but highest among patients. Conclusion: These data support the hypothesis that COMT polymorphisms may be associated with schizophrenia and modulate cognition in patients and controls.

Effects and Mechanisms of Radiofrequency Ablation of Renal Sympathetic Nerve on Anti-Hypertension in Canine / Efeitos e Mecanismos da Denervação Simpática Renal por Radiofrequência na Anti-Hipertensão em Cães

Abstract Background: Radiofrequency ablation of renal sympathetic nerve (RDN) shows effective BP reduction in hypertensive patients while the specific mechanisms remain unclear. Objective: We hypothesized that abnormal levels of norepinephrine (NE) and changes in NE-related enzymes and angiotensinconverting enzyme 2 (ACE2), angiotensin (Ang)-(1-7) and Mas receptor mediate the anti-hypertensive effects of RDN. Methods: Mean values of systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP) were assessed at baseline and follow-up. Plasma and renal norepinephrine (NE) concentrations were determined using highperformance liquid chromatography with electrochemical detection, and levels of NE-related enzyme and ACE2-Ang(1-7)- Mas were measured using real time PCR, Western blot and immunohistochemistry or Elisa in a hypertensive canine model fed with high-fat diet and treated with RDN. The parameters were also determined in a sham group treated with renal arteriography and a control group fed with normal diet. Results: RDN decreased SBP, DBP, MAP, plasma and renal NE. Compared with the sham group, renal tyrosine hydroxylase (TH) expression was lower and renalase expression was higher in the RDN group. Compared with the control group, renal TH and catechol-o-methyl transferase (COMT) were higher and renalase was lower in the sham group. Moreover, renal ACE2, Ang-(1-7) and Mas levels of the RDN group were higher than those of the sham group, which were lower than those of the control group. Conclusion: RDN shows anti-hypertensive effect with reduced NE and activation of ACE2-Ang(1-7)-Mas, indicating that it may contribute to the anti-hypertensive effect of RDN.

Resumo Fundamentos: A denervação simpática renal por radiofrequência (DSR) mostra redução eficaz da pressão arterial (PA) de pacientes hipertensos, ainda que os mecanismos específicos permaneçam obscuros. Objetivo: Fizemos a hipótese de que níveis alterados de noradrenalina (NA) e mudanças nas enzimas relacionadas à NA e enzima conversora de angiotensina 2 (ECA-2), angiotensina (Ang)-(1-7) e receptor Mas são mediadores dos efeitos antihipertensivos da DSR. Métodos: Foram avaliados os valores médios de pressão arterial sistólica (PAS), pressão arterial diastólica (PAD) e pressão arterial média (PAM) no início e durante o seguimento. Foram medidas as concentrações plasmática e renal de noradrenalina (NA) por cromatografia líquida de alta eficiência com detecção eletroquímica, e os níveis de enzima relacionada à NA e ECA2-Ang-(1-7)-Mas através de PCR em tempo real, Western blot e imunohistoquímica ou Elisa em um modelo canino de hipertensão que recebeu ração rica em gordura e foi tratado com DSR. Os parâmetros também foram determinados em um grupo de cirurgia simulada submetido à arteriografia renal e em um grupo controle que recebeu dieta normal. Resultados: DSR causou diminuição da PAS, PAD, PAM e das concentrações plasmática e renal de NA. Em comparação ao grupo placebo, a expressão da tirosina hidroxilase (TH) renal foi menor e a da renalase foi maior no grupo DSR. Em comparação ao grupo controle, os níveis de TH renal e de catecol-o-metil-transferase (COMT) foram maiores e os de renalase foram menores no grupo cirurgia simulada. Além disso, os níveis renais de ECA2, Ang-(1-7) e Mas foram maiores no grupo DSR do que no grupo cirurgia simulada, que, por sua vez, foram menores do que no grupo controle. Conclusões: A DSR mostra efeitos anti-hipertensivos com redução da NA e ativação da ECA2-Ang-(1-7)-Mas, o que indica que pode contribuir com o efeito anti-hipertensivo da DSR.

Genetic Polymorphism of 1019C/G (rs6295) Promoter of Serotonin 1A Receptor and Catechol-O-Methyltransferase in Panic Disorder

OBJECTIVE: Family and twin studies have suggested genetic liability for panic disorder (PD) and therefore we sought to determine the role of noradrenergic and serotonergic candidate genes for susceptibility for PD in a Japanese population. METHODS: In this age- and gender-matched case-control study involving 119 PD patients and 119 healthy controls, we examined the genotype distributions and allele frequencies of the serotonin transporter gene linked polymorphic region (5-HTTLPR), −1019C/G (rs6295) promoter polymorphism of the serotonin receptor 1A (5-HT1A), and catechol-O-methyltransferase (COMT) gene polymorphism (rs4680) and their association with PD. RESULTS: No significant differences were evident in the allele frequencies or genotype distributions of the COMT (rs4680), 5-HTTLPR polymorphisms or the −1019C/G (rs6295) promoter polymorphism of 5-HT1A between PD patients and controls. Although there were no significant associations of these polymorphisms with in subgroups of PD patients differentiated by gender or in subgroup comorbid with agoraphobia (AP), significant difference was observed in genotype distributions of the −1019C/G (rs6295) promoter polymorphism of 5-HT1A between PD patients without AP and controls (p=0.047). CONCLUSION: In this association study, the 1019C/G (rs6295) promoter polymorphism of the 5-HT1A receptor G/G genotype was associated with PD without AP in a Japanese population.

Research progress on molecular genetics of male homosexuality / 中华医学遗传学杂志

Sexual orientation is influenced by both environmental factors and biological factors. Family and twin studies have shown that genetic factors play an important role in the formation of male homosexuality. Genome-wide scan also revealed candidate chromosomal regions which may be associated with male homosexuality, but so far no clearly related genes have been found. This article reviews the progress of relevant studies and candidate genes which are related to male homosexuality.

Association between COMT and 5-HTTLPR Polymorphisms in Korean Patients with Panic Disorder : A Replication Study

OBJECTIVES: We investigated whether the catechol-O-methyltransferase (COMT) and serotonin related gene polymorphisms may be associated with agoraphobia in patients with panic disorder in Korea. METHODS: The COMT gene (rs4680), 5-hydroxytryptamine (serotonin) transporter linked polymorphic region (5-HTTLPR) gene (rs25531), serotonin receptor 1A (HTR1A) gene (rs6295) genotypes were analyzed in 406 patients with panic disorder and age-sex matched 206 healthy controls. Patients with panic disorder were dichotomized by the presence of agoraphobia. The following instruments were applied : the Beck Depression Inventory, the Beck Anxiety Inventory, the Panic Disorder Severity Scale. RESULTS: There was a significant difference in the distribution of 5-HTTLPR genotype between panic patients with agoraphobia and without agoraphobia (p = 0.024). That is, the panic patients with agoraphobia had a significant excess of the less active 5-HTTLPR allele (S allele). (p = 0.039) Also, we replicated previous western reports which indicated a significant difference in the distribution of COMT genotype between the patients with panic disorder and the healthy controls (p = 0.040). However, no significant associations of agoraphobia or panic disorder with HTR1A gene polymorphisms were found. CONCLUSIONS: This result supports that the COMT polymorphisms may be associated with panic disorder and suggests that the 5-HTTLPR polymorphisms may play a role in the pathogenesis of agoraphobia in the Korean patients with panic disorder.

The Effect of Single Dose Methylphenidate on Neurometabolites according to COMT Gene Val158Met Polymorphism in the Patient with Attention Deficit Hyperactivity Disorder: A Study Using Magnetic Resonance Spectroscopy

OBJECTIVE: Attention deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder. Thus, the present study aimed to determine the effects of a single dose of methylphenidate (Mph) on neurometabolite levels according to polymorphisms of the catechol-O-methyltransferase (COMT) gene. METHODS: This study evaluated the neurometabolite levels including N-acetylaspartate (NAA), creatine (Cr), and choline (Cho) of ADHD patients, before and after treatment with Mph (10 mg) according to the presence of COMT polymorphisms. The spectra were obtained from the dorsolateral prefrontal cortex (DLPFC), anterior cingulate cortex (ACC), cerebellum, and striatum. RESULTS: The NAA levels of the val/val and val genotype carriers (val/val and val/met genotypes) increased in the DLPFC and ACC, respectively, following Mph treatment. The NAA/Cr ratio was lower in the DLPFC of val carriers than in the met/met genotype carriers prior to Mph administration. The Cho levels of the val/met genotype and val carriers increased in the striatum following Mph treatment. Following Mph treatment, the Cr levels of the met/met genotype carriers were higher than those of the val/met genotype and val carriers. Additionally, after Mph treatment, there was a significant increase in Cr levels in the DLPFC of the met/met genotype carriers but a significant decrease in such levels in the striatum of val/val genotype carriers. CONCLUSION: These findings suggest that polymorphisms of the COMT gene can account for individual differences in neuro-chemical responses to Mph among ADHD patients. Therefore, further studies are needed to fully characterize the effects of the Val158met polymorphism of the COMT gene on treatment outcomes in patients with ADHD.

Serotonin Transporter and COMT Polymorphisms as Independent Predictors of Health-related Quality of Life in Patients with Panic Disorder

There is growing evidence of poor health-related quality of life (HRQOL) in patients with panic disorder (PD). However, little is known about the factors affecting HRQOL in patients with PD. The authors examined whether 5-HTTLPR tri-allelic approach and Cathechol-O-methyltransferase (COMT) Val(158)Met polymorphism can predict HRQOL in patients with PD controlling for sociodemographic factors and disorder-related symptom levels. The sample consisted of 179 patients with PD consecutively recruited from an outpatient clinic and age- and gender ratio-matched 110 healthy controls. The SF-36 was used to assess multiple domains of HRQOL. Hierarchical multiple regression analysis was performed to determine the independent effect of the 5-HTTLPR and COMT Val(158)Met on the SF-36 in panic patients. Patients with PD showed lowered HRQOL in all sub-domains of the SF-36 compared to healthy controls. The 5-HTTLPR independently and additively accounted for 2.2% of variation (6.7% of inherited variance) of perceived general health and the COMT Val(158)Met independently and additively accounted for 1.5% of variation (5.0% of inherited variance) of role limitation due to emotional problems in patient group. The present study suggests that specific genetic polymorphisms are associated with certain domains of HRQOL and provides a new insight on exploring the factors that predict HRQOL in patients with PD.

Association between the Catechol-O-Methyltransferase (COMT) Val(158)Met Polymorphism and Alexithymia in Patients with Obsessive-Compulsive Disorder

PURPOSE: Alexithymia, defined as a deficit in the ability to recognize and describe one's own feelings, may be related to the development and maintenance of obsessive-compulsive symptoms. The aim of this study was to evaluate the association between the catechol-O-methyltransferase (COMT) Val158Met polymorphism and alexithymia in patients with obsessive-compulsive disorder (OCD). MATERIALS AND METHODS: We recruited 244 patients with OCD (169 males, 75 females). Alexithymia was assessed using the 20-item Toronto Alexithymia Scale (TAS-20), and genotyping of the COMT Val(158)Met polymorphism was evaluated. RESULTS: Patients with the COMT Val/Val genotype had significantly higher total and "difficulty identifying feelings" (DIF) subdimension scores than those with the Val/Met or Met/Met genotypes. Patients with the COMT Val/Val genotype had significantly higher "difficulty describing feelings" (DDF) subdimension scores than those with the COMT Val/Met genotype. However, there were no differences in the scores for the "externally oriented thinking" (EOT) subdimension among the three genotypes. CONCLUSION: These results indicate that the high-activity Val allele of the COMT Val(158)Met polymorphism is associated with increased alexithymic traits in patients with OCD. The present finding suggests that alexithymia is an endophenotype of OCD that is mediated by the COMT Val(158)Met polymorphism.

Genetic Variations in Attention Deficit Hyperactivity Disorder Subtypes and Treatment Resistant Cases

OBJECTIVE: ObjectiveaaWe evaluated the distribution of alpha-2A adrenergic receptor (ADRA2A) and catechol-o-methyltransferase (COMT) single nucleotide polymorphisms (SNPs) among ADHD subtypes and other homogeneous patient populations including treatment-resistant cases and patients with high symptom severity. METHODS: Methodsaa121 ADHD patients aged 6-18 years were included in the study. Diagnosis and subtypes designation were confirmed using the Kiddie Schedule for Affective Disorders and Schizophrenia (K-SADS) and symptoms were evaluated using the Conners' Parent (CPRS) and Teacher Rating Scales (CTRS). The response to methylphenidate was assessed objectively using the Clinical Global Impression-Severity Scale (CGI-S) and Global Assessment of Functioning Scale (GAS) as well as the Continuous Performance (CPT) and Trail Making tests (TMT-A, B). Patients were genotyped for ADRA2A (rs1800544) and COMT (rs4680) SNPs by PCR/RFLP and compared to a gender-matched control group. RESULTS: Although there was no association of COMT (rs4680) SNP with symptoms or diagnosis, the ADRA2A polymorphism, low socioeconomic status (SES), and comorbid psychiatric diagnosis were all associated with poor response to methylphenidate in logistic regression analysis. CONCLUSION: Clinicians may consider adjuvant strategies when these negative factors are present to increase the success of tailored ADHD treatments in the future.

Research Progress on Abused Drugs Metabolic in vivo / 法医学杂志

Under the catalysis of a variety of metabolic enzymes in vivo, such as UDP-glucuronyl transferases, cytochrome P450, carboxylesterase, sulfotransferase, butyrylcholinesterase, catechol-O-methyl transferase and 6-morphine dehydrogenase, the drugs perform glucuronidation, hydrolysis, oxidation, sulfonation and other reactions, then translate into active or inactive metabolites, which are excreted through urination, bile or the other pathways at last. Different drugs own their different metabolic pathways. This paper introduces the studies about the metabolism of drugs in human and animal in recent years, such as morphine-like drugs, amphetamine, ketamine, cannabis and cocaine, and reviews the research progress about the sites of metabolism, metabolic enzymes, metabolites and physiological activity of those drugs metabolic in vivo.

Epistasis between COMT Val158Met and DRD3 Ser9Gly polymorphisms and cognitive function in schizophrenia: genetic influence on dopamine transmission

Objective:To assess the relationship between cognitive function, a proposed schizophrenia endophenotype, and two genetic polymorphisms related to dopamine function, catechol-O-methyl transferase (COMT) Val158Met and dopamine receptor 3 (DRD3) Ser9Gly.Methods:Fifty-eight outpatients with schizophrenia/schizoaffective disorder and 88 healthy controls underwent neurocognitive testing and genotyping. Analyses of covariance (ANCOVAs) using age, sex, and years of education as covariates compared cognitive performance for the proposed genotypes in patients and controls. ANCOVAs also tested for the epistatic effect of COMT and DRD3 genotype combinations on cognitive performance.Results:For executive functioning, COMT Val/Val patients performed in a similar range as controls (30.70-33.26 vs. 35.53-35.67), but as COMT Met allele frequency increased, executive functioning worsened. COMT Met/Met patients carrying the DRD3 Ser/Ser genotype performed poorest (16.184 vs. 27.388-31.824). Scores of carriers of this COMT/DRD3 combination significantly differed from all DRD3 Gly/Gly combinations (p < 0.05), from COMT Val/Met DRD3 Ser/Gly (p = 0.02), and from COMT Val/Val DRD3 Ser/Ser (p = 0.01) in patients. It also differed significantly from all control scores (p < 0.001).Conclusion:Combined genetic polymorphisms related to dopamine neurotransmission might influence executive function in schizophrenia. Looking at the effects of multiple genes on a single disease trait (epistasis) provides a comprehensive and more reliable way to determine genetic effects on endophenotypes.

Association of single nucleotide polymorphisms of ABCB1, OPRM1 and COMT with pain perception in cancer patients / 华中科技大学学报（医学）（英德文版）

Pain perception is influenced by multiple factors. The single nucleotide polymorphisms (SNPs) of some genes were found associated with pain perception. This study aimed to examine the association of the genotypes of ABCB1 C3435T, OPRM1 A118G and COMT V108/158M (valine 108/158 methionine) with pain perception in cancer patients. We genotyped 146 cancer pain patients and 139 cancer patients without pain for ABCB1 C3435T (rs1045642), OPRM1 A118G (rs1799971) and COMT V108/158M (rs4680) by the fluorescent dye-terminator cycle sequencing method, and compared the genotype distribution between groups with different pain intensities by chi-square test and pain scores between groups with different genotypes by non-parametric test. The results showed that in these cancer patients, the frequency of variant T allele of ABCB1 C3435T was 40.5%; that of G allele of OPRM1 A118G was 38.5% and that of A allele of COMT V108/158M was 23.3%. No significant difference in the genotype distribution of ABCB1 C3435T (rs1045642) and OPRM1 A118G (rs1799971) was observed between cancer pain group and control group (P=0.364 and 0.578); however, significant difference occurred in the genotype distribution of COMT V108/158M (rs4680) between the two groups (P=0.001). And the difference could not be explained by any other confounding factors. Moreover, we found that the genotypes of COMT V108/158M and ABCB1 C3435T were associated with the intensities of pain in cancer patients. In conclusion, our results indicate that the SNPs of COMT V108/158M and ABCB1 C3435T significantly influence the pain perception in Chinese cancer patients.

Effect of Polymorphisms of Three Genes Mediating Monoamine Signalling on Brain Morphometry in Schizophrenia and Healthy Subjects

OBJECTIVE: We examined the effect of risk alleles of polymorphisms of three schizophrenia risk genes that mediate monoamine signalling in the brain on regional brain volumes of schizophrenia and healthy control subjects. The risk alleles and the gene polymorphisms studied were: Val allele of catechol o-methyltransferase (COMT) rs4680 polymorphism; short allele of 5-hydroxy tryptamine transporter linked polymorphic region (5HTTLPR) polymorphism; and T allele of 5-hydroxy tryptamine 2A (5HT2A) rs6314 polymorphism. METHODS: The study was carried out on patients with recent onset schizophrenia (n=41) recruited from the outpatient department of National Institute of Mental Health and Neurosciences, Bangalore, India and healthy control subjects (n=39), belonging to South Indian Dravidian ethnicity. Individual and additive effects of risk alleles of the above gene polymorphisms on brain morphometry were explored using voxel-based morphometry. RESULTS: Irrespective of phenotypes, individuals with the risk allele T of the rs6314 polymorphism of 5HT2A gene showed greater (at cluster-extent equivalent to family wise error-correction [FWEc] p<0.05) regional brain volumes in the left inferior temporal and left inferior occipital gyri. Those with the risk alleles of the other two polymorphisms showed a trend (at p<0.001, uncorrected) towards lower regional brain volumes. A trend (at p<0.001, uncorrected) towards additive effects of the above 3 risk alleles (subjects with 2 or 3 risk alleles vs. those with 1 or no risk alleles) on brain morphology was also noted. CONCLUSION: The findings of the present study have implications in understanding the role of individual and additive effects of genetic variants in mediating regional brain morphometry in health and disease.

Polymorphisms of catechol-O-methyltransferase and monoamine oxidase B genes among Chinese patients with Parkinson's disease / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To study polymorphisms of catechol-O-methyltransferase (COMT) and monoamine oxidase B (MAO-B) genes among Chinese patients with Parkinson's disease.</p><p><b>METHODS</b>Genotypes of the COMT and MAO-B genes of 1408 patients with Parkinson's disease was sequenced using Sanger method. And these patients were recruited by Chinese Parkinson Study Group from 29 research centers throughout the country.</p><p><b>RESULTS</b>The genotypic frequencies of COMT rs4680 AA, AG, GG were 8.9%, 42.0% and 49.1%. Those of rs4818 CC, CG, GG were 42.5%, 45.6% and 11.9%, respectively. The genotype frequencies of MAO-B rs1799836 A/AA, AG, G/GG were 74.4%, 14.1% and 11.5%, respectively. The haplotype formed by COMT rs4680 (GG) and MAO-B rs1799836 (A/AA) genotype has a frequency of 36.86%.</p><p><b>CONCLUSION</b>Polymorphisms of COMT and MAO-B genes has a unique characteristics among Chinese patients with Parkinson's disease. They may be related with differences in drug response in such patients.</p>

Difference in brain surface area between first-episode familial and sporadic schizophrenia and its association with COMT gene polymorphisms / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To assess the association of impairment of surface area of first-episode schizophrenia(SZ) with polymorphisms of COMT gene, and the difference in the impaired patterns between familial patients with schizophrenia(FPS) and sporadic patients with schizophrenia(SPS).</p><p><b>METHODS</b>Ninety-eight patients with first-episode SZ(FPS=40, SPS=58) and 78 healthy controls were recruited. COMT gene was genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Participants were scanned for 3.0T magnetic resonance images. Freesurfer software was used to analyze the difference in brain surface area between SZ and controls, its association with COMT genotypes, and the difference between SPS, FPS and control groups. Multiple tests were corrected using a Monte Carlo simulation at P<0.05.</p><p><b>RESULTS</b>Compared with controls, SZ showed decreased surface area in right occipital cortex and left prefrontal cortex. No association was found between COMT polymorphisms and whole brain area difference. Among the three subgroups, SPS showed smaller left prefrontal area compared with both FPS and control groups. Patients with SPS also showed significant area reduction in right occipital lobe compared with controls.</p><p><b>CONCLUSION</b>Surface area impairment can be found in those with first-episode SZ, but without association with COMT gene polymorphisms. The SPS have more severe area impairment than FPS, indicating that SPS and FPS may be attributed to different etiological mechanisms.</p>