catechol-O-methyltransferase Genotype Research Articles

Effect of Catechol-O-Methyltransferase Genotype Polymorphism on Neurological and Psychiatric Disorders: Progressing Towards Personalized Medicine.

Different polymorphisms of the catechol-O-methyltransferase (COMT) gene affect the COMT enzyme activity. The COMT enzyme plays a major role in the pathophysiology of various neurological and psychiatric disorders. This review article aims to discuss what recent research has discovered about the association of COMT genotype polymorphism with neurological and psychiatric disorders and the scope for the knowledge to be applied for advancement in therapeutics. We searched PubMed and Google Scholar databases and found 1656 articles. We included observational studies, clinical trials, and meta-analyses in the English language published between 2019 and 2021. We screened the articles based on the title and the abstract and found 26 relevant articles. Diseases or conditions studied primarily were schizophrenia, Parkinson’s disease, Alzheimer’s disease, substance use, and depression. This article highlights how genetics influences the susceptibility of an individual to neurological and psychiatric diseases and the variations in the specific symptoms of those diseases. The review showed that the variability in individual response to therapeutic interventions stems from the gene level. This knowledge can contribute towards the dawn of a new era of personalized medicine.

Enhancing dopamine tone modulates global and local cortical perfusion as a function of COMT val158met genotype

The cognitive effects of pharmacologically enhancing cortical dopamine (DA) tone are variable across healthy human adults. It has been postulated that individual differences in drug responses are linked to baseline cortical DA activity according to an inverted-U-shaped function. To better understand the effect of divergent starting points along this curve on DA drug responses, researchers have leveraged a common polymorphism (rs4680) in the gene encoding the enzyme catechol-O-methyltransferase (COMT) that gives rise to greater (Met allele) or lesser (Val allele) extracellular levels of cortical DA. Here we examined the extent to which changes in resting cortical perfusion following the administration of two mechanistically-distinct dopaminergic drugs vary by COMT genotype, and thereby track predictions of the inverted-U model. Using arterial spin labeling (ASL) and a double-blind, within-subject design, perfusion was measured in 75 healthy, genotyped participants once each after administration of tolcapone (a COMT inhibitor), bromocriptine (a DA D2/3 agonist), and placebo. COMT genotype and drug interacted such that COMT Val homozygotes exhibited increased prefusion in response to both drugs, whereas Met homozygotes did not. Additionally, tolcapone-related perfusion changes in the right inferior frontal gyrus correlated with altered performance on a task of executive function. No comparable effects were found for a genetic polymorphism (rs1800497) affecting striatal DA system function. Together, these results indicate that both the directionality and magnitude of drug-induced perfusion change provide meaningful information about individual differences in response to enhanced cortical DA tone.

Pregnancy-related hormones and COMT genotype: Associations with maternal working memory

Women experience different degrees of subjective cognitive changes during pregnancy. The exact mechanism underlying these changes is unknown, although endocrine alterations and genetics may be contributing factors. We investigated whether multiple pregnancy-related hormones were associated with working memory function assessed with the Digit Span Test (DST) in late pregnancy. Moreover, we examined whether the catechol-O-methyltransferase (COMT) genotype, previously related to working memory, was an effect modifier in this association.In this population-based panel study, we recorded psychiatric history, medication use, socio-demographic characteristics, and psychological well-being, gathered blood and saliva samples, and administered the DST at gestational weeks 35–39 (N = 216). We conducted multivariate linear regressions with DST as outcome, with different hormones and COMT genotype, adjusting for covariates including maternal age, BMI, education, depressive symptoms, and parity. We repeated these analyses excluding women with elevated depressive symptoms.Higher DST total scores were associated with increased free estradiol concentrations (B = 0.01, p = 0.03; B = 0.01, p = 0.02) in all participants and in participants without depressive symptoms, respectively, whereas DST forward was positively associated with free estradiol only in women without depressive symptoms (B = 0.01, p = 0.04). Lower total testosterone concentrations (B = −0.03, p = 0.01) enhanced DST backward performance in non-depressed women. Maternal higher education was significantly associated with the DST subscales in all participants. No significant differences emerged when considering the COMT genotype.Our results suggest differential associations of free estradiol and total testosterone levels with working memory function in late pregnancy.

Association of COMT Polymorphism and Academic Achievement among Female Undergraduate Students

Academic achievement may be influenced by catechol-O-methyltransferase (COMT) polymorphism. A common functional polymorphism of COMT, the rs4680 is consistently being involved in the modulation of dopaminergic pathway and prefrontal cortex function which may predominantly affect cognitive functions. A total of 197 female participants were recruited in this study. The score of student’s grade point average (GPA) from the latest previous semester was used as the measurement of academic achievement. The COMT polymorphism was genotyped using tetra primer allele specific polymerase chain reaction. The findings indicated that there were 8 (4.1 %), 72 (36.5 %), and 117 (59.4 %) participants harbouring Met/Met, Met/Val, and Val/Val genotype for COMT polymorphism respectively. All the genotype distributions of COMT polymorphism were consistent with Hardy-Weinberg equilibrium (χ2 = 0.495, p > 0.05). The one-way analysis of variance (ANOVA) result demonstrated that participants bearing Met/Met genotype had a better achievement in GPA as compared to the other COMT genotypes (p = 0.001). These findings support evidence that the affective role of COMT polymorphism might overwhelm cognitive abilities in measures of academic achievement like GPA.

The Effect of 12-Month Green Tea Extract Supplementation and Impact of Catechol-O-Methyltransferase Genotype on Blood Pressure in Women Who Are Post-menopause

Abstract Objectives Green tea extract (GTE) is thought to have antihypertensive properties, potentially mediated by epigallocatechin gallate (EGCG). The objective of this study was to evaluate the effect of GTE supplementation on blood pressure (BP) among postmenopausal women with elevated BP or hypertension (HTN). Methods This study was a secondary analysis of the Minnesota Green Tea Trial (MGTT), a randomized, placebo-controlled, double-blinded trial in which healthy, postmenopausal women were randomized to consume GTE (two capsules each morning and evening with meals, 843 mg/day of EGCG) or placebo, daily for 12 months. MGTT subjects who had elevated BP or HTN at baseline (N = 495) were included. Primary outcomes were changes in systolic (SBP) and diastolic (DBP) blood pressure. Chi-square, Fisher's exact, Independent samples t-test, and ANCOVA adjusting for baseline BP and weight changes, were conducted to evaluate frequency distributions and between-group differences. Findings were stratified by age, BMI, use of antihypertensive medication, BP status, and catechol-O-methyltransferase (COMT) genotype. Results Ninety-seven % of subjects were white and non-Hispanic. The sample had a mean age of 61.0 years and mean BMI of 25.9 kg/m2 at baseline. There were no significant differences in SBP or DBP changes between treatment groups in the total sample, or between COMT genotypes (low-activity versus high-activity) within the GTE group. However, there were significant interactions between treatment group and baseline BMI (P = 0.02), and baseline age (P = 0.03). Significant reductions in mean SBP in response to GTE were observed in subjects with BMI of 18.5–24.9 kg/m2 (−6.7 mmHg, P = 0.005), and subjects aged 61–70 years (−6.0 mmHg, P = 0.004), compared to subjects with BMI ≥ 25.0 kg/m2 and those aged 50–60 years. There were no significant interactions between treatment group and baseline BP status or baseline use of antihypertensive medication. Conclusions GTE may reduce SBP in postmenopausal women aged 61–70 years and those with normal weight status. Questions for future research may include the optimal dosage and duration of GTE supplementation, and the relative bioavailability and effectiveness of GTE capsules versus green tea beverages. Funding Sources NIH/National Cancer Institute.

Influence of COMT polymorphism in cognitive performance on dementia in community-dwelling elderly Mexican (SADEM study).

There is an inconsistent finding about the relationship of catechol-O-methyltransferase (COMT) with dementia susceptibility, as well as with cognitive impairment. To substantiate this, we examined COMT genotype effects in certain cognitive domains in dementia. To evaluate the effects of COMT Val158Met on cognitive performance, we used The Mini-Mental State Examination (MMSE), the cognitive subscale of the Alzheimer's Disease Assessment Scale-cognitive (ADAS-cog) and the Syndrome Kurz Test (SKT). The results show COMT Val/Met, Val/Val genotype polymorphisms had a significant effect on cognition performance (OR = 1.75 (95%CI 1.22-2.54) and (OR = 2.76 (95%CI 1.78-4.26), p < 0.001), and with adjustment for all cognitive test scores together, Val/Val (OR = 4.98 (95 % CI 1.47-16.86) and Val/Met (OR = 3.62 (95 % CI 1.37-9.56) had effect. Our study allows us to understand the role of COMT in cognitive performance in dementia, as well as interaction with other known risk factors for this pathology. This data might help in developing new therapeutic targets for cognitive impairment, main symptom of dementia. Other risk genotypes or haplotypes should be evaluated to determine the association with cognitive decline in dementia.

Stimulant treatment effectiveness, safety and risk for psychosis in individuals with 22q11.2 deletion syndrome.

This study aimed to retrospectively evaluate an association between stimulant treatment for attention-deficit/hyperactivity disorder (ADHD) in individuals with 22q11.2DS and the development of psychotic disorders, to evaluate long-term effectiveness and safety of stimulant treatment in individuals with 22q11.2DS compared to individuals with idiopathic ADHD, and to explore effects of catechol-O-methyltransferase (COMT) genotype on 22q11.2DS response to stimulants and risk of side effects. Rates of stimulant use and methylphenidate equivalent exposure were compared among individuals with 22q11.2DS, between 51 with psychotic disorders and a control group of 57 22q11.2DS without psychotic disorders, from Tel Aviv and Geneva. In addition, 44 individuals with 22q11.2DS and ADHD from Tel Aviv who initiated stimulants before age 18years were compared to a control group of 35 age- and sex-matched controls with idiopathic ADHD, for treatment effectiveness (Clinical Global Impression Scale-Improvement), and rates of side effects. Stimulant use history and methylphenidate equivalent exposure did not differ among individuals with 22q11.2DS, between those with and without psychotic disorders. The long-term retrospective follow-up (5.3 ± 4.1years) of stimulant-treated individuals with 22q11.2DS showed a higher rate of significant clinical improvement of ADHD symptoms, compared to idiopathic ADHD individuals (p = 0.013), and similar side effect rates. There was no effect of the COMT genotype on response to stimulants or on any side effects. This preliminary long-term retrospective analysis suggests that stimulant treatment in 22q11.2DS is apparently safe in terms of psychosis conversion and rates of side effects, and that it is effective in alleviating ADHD symptoms.

8 Variations in COMT Gene Are Not Associated with Patient-Reported Outcomes: A Multicenter Collaborative Proof of Concept Study

Abstract Introduction Variant single nucleotide polymorphisms (SNPs) in the catechol-O-methyl transferase (COMT) gene have previously been associated with pain thresholds, resiliency, and cognitive functioning. Known colloquially as the “warrior/worrier” gene, the GG variant is associated with higher resilience whereas the AA variant is associated with lower resilience. The aim of this study is to demonstrate the feasibility of correlating a genomic data repository with multicenter national longitudinal burn data. Methods From August 2018 to July 2020, participant cheek swabs were collected in-person or by mail at three burn centers and sent to the lead center for DNA isolation and storage. COMT SNPs were determined by polymerase chain reaction (PCR). SNP data were merged with a multicenter burn database. Outcomes of interest included the Patient-Reported Outcomes Measurement Information System (PROMIS-29), Community Integration Questionnaire (CIQ), Veterans RAND 12 (VR-12) physical (PCS) and mental component summary (MCS) scores, posttraumatic stress disorder (PTSD) measure, and Posttraumatic Growth Inventory (PTGI). Follow-up data were obtained at 6 months post-discharge. We used a Kruskal-Wallis test to determine associations between COMT SNPs and outcomes. Results Of the 126 cheek swabs obtained, DNA was successfully isolated from 124 swabs, and PCR SNP analysis was successful for 111 swabs. The distribution of COMT SNPs in our study population was consistent with the general population. Kruskal-Wallis analysis revealed no association between COMT SNPs and patient outcomes. Median PTGI scores trended toward significance, but in the opposite direction than predicted for COMT genotypes. Conclusions A national longitudinal database can be feasibly supplemented by a genomic data repository. Variation in the COMT gene did not correlate with health-related quality of life measures examined in a small cohort of burn survivors. Lack of statistical significance can be attributed to small sample size.

Dopaminergic modulation of regional cerebral blood flow: An arterial spin labelling study of genetic and pharmacological manipulation of COMT activity

Dopamine has direct and complex vasoactive effects on cerebral circulation. Catechol-O-methyltransferase (COMT) regulates cortical dopamine, and its activity can be influenced both genetically and pharmacologically. COMT activity influences the functional connectivity of the PFC at rest, as well as its activity during task performance, determined using blood oxygen level-dependent (BOLD) fMRI. However, its effects on cerebral perfusion have been relatively unexplored. Here, 76 healthy males, homozygous for the functional COMT Val158Met polymorphism, were administered either the COMT inhibitor tolcapone or placebo in a double-blind, randomised design. We then assessed regional cerebral blood flow at rest using pulsed arterial spin labelling. Perfusion was affected by both genotype and drug. COMT genotype affected frontal regions (Val158 > Met158), whilst tolcapone influenced parietal and temporal regions (placebo > tolcapone). There was no genotype by drug interaction. Our data demonstrate that lower COMT activity is associated with lower cerebral blood flow, although the regions affected differ between those affected by genotype compared with those altered by acute pharmacological inhibition. The results extend the evidence for dopaminergic modulation of cerebral blood flow. Our findings also highlight the importance of considering vascular effects in functional neuroimaging studies, and of exercising caution in ascribing group differences in BOLD signal solely to altered neuronal activity if information about regional perfusion is not available.

Maternal rearing styles and loneliness: The moderating role of the COMT Val158Met polymorphism

Loneliness is a common problem in adulthood, with deleterious effects on mental health. In the present study, we examined whether the effects of maternal rearing styles on loneliness are moderated by the catechol-O-methyltransferase (COMT) Val158Met polymorphism and whether loneliness can further affect mental health as a mediator in 1034 genotyped participants. The results showed that the COMT genotype significantly moderated the relationship between maternal rejection and loneliness; more specifically, Val carriers who perceived higher levels of rejection from their mothers demonstrated higher levels of loneliness. The moderated mediation model revealed that loneliness meditated the indirect effects of maternal rejection on life satisfaction. Specifically, for individuals with the Val/Val genotype, higher rejection from their mothers had a greater influence on their life satisfaction through loneliness. In addition, we found that the effect of COMT Val158Met maternal rejection on loneliness and the effect of maternal rejection on Val/Val adults’ life satisfaction via loneliness existed across different age groups. These findings provide a new understanding of the gene–parenting interaction effect on loneliness and its influence on mental health.

Aberrant Brain Signal Variability and COMT Genotype in Chronic TMD Patients

The analysis of brain signal variability is a promising approach to understand pathological brain function related to chronic pain. This study investigates whether blood-oxygen-level–dependent signal variability (BOLDSV) in specific frequency bands is altered in temporomandibular disorder (TMD) and correlated to its clinical features. Twelve patients with chronic myofascial TMD and 24 healthy controls (HCs) underwent resting-state functional magnetic resonance imaging. The BOLDSV was measured as the standard deviation of the BOLD time series at each voxel and compared between groups. We also examined the potential relationship between the BOLDSV and the catechol-O-methyltransferase (COMT) Val158Met polymorphism. We assessed sensory-discriminative pain in the craniofacial region, pain sensitivity to sustained masseteric pain challenge, and TMD pain frequency for clinical correlation. Patients displayed reduced BOLDSV in the dorsolateral prefrontal cortex (dlPFC) as compared with HC in all frequency bands. In the slow-3 band, patients also showed reduced BOLDSV in the medial dorsal thalamus, primary motor cortex (M1), and primary somatosensory cortex (S1) and heightened BOLDSV in the temporal pole. Notably, we found a significant correlation between lower BOLDSV (slow-3) in the orofacial M1/S1 regions and higher clinical pain (intensity/area) and higher sensitivity of the masseter muscle pain. Moreover, lower BOLDSV (slow-3) in the dlPFC and ventrolateral PFC was associated with a higher TMD pain frequency. Participants who had the COMT 158Met substitution exhibited lower BOLDSV in the dlPFC and higher BOLDSV in the temporal pole as compared with participants without the COMT 158Met substitution. An increasing number of Met alleles was associated with lower dlPFC and greater temporal pole BOLDSV in both HC and TMD groups. Together, we demonstrated that chronic TMD patients exhibit aberrant BOLDSV in the top-down pain modulatory and sensorimotor circuits associated with their pain frequency and severity. COMT Val158Met polymorphism might affect clinical symptoms in association with regional brain signal variability, specifically involved in cognitive and emotional regulation of pain.

Population pharmacokinetics of levodopa gel infusion in Parkinson\u2019s disease: effects of entacapone infusion and genetic polymorphism

Levodopa-entacapone-carbidopa intestinal gel (LECIG) provides continuous drug delivery through intrajejunal infusion. The aim of this study was to characterize the population pharmacokinetics of levodopa following LECIG and levodopa-carbidopa intestinal gel (LCIG) infusion to investigate suitable translation of dose from LCIG to LECIG treatment, and the impact of common variations in the dopa-decarboxylase (DDC) and catechol-O-methyltransferase (COMT) genes on levodopa pharmacokinetics. A non-linear mixed-effects model of levodopa pharmacokinetics was developed using plasma concentration data from a double-blind, cross-over study of LCIG compared with LECIG in patients with advanced Parkinson’s disease (n = 11). All patients were genotyped for rs4680 (polymorphism of the COMT gene), rs921451 and rs3837091 (polymorphisms of the DDC gene). The final model was a one compartment model with a high fixed absorption rate constant, and a first order elimination, with estimated apparent clearances (CL/F), of 27.9 L/h/70 kg for LCIG versus 17.5 L/h/70 kg for LECIG, and apparent volume of distribution of 74.4 L/70 kg. Our results thus suggest that the continuous maintenance dose of LECIG, on a population level, should be decreased by approximately 35%, to achieve similar drug exposure as with LCIG. An effect from entacapone was identified on all individuals, regardless of COMT rs4680 genotype. The individuals with higher DDC and COMT enzyme activity showed tendencies towards higher levodopa CL/F. The simultaneous administration of entacapone to LCIG administration results in a 36.5% lower apparent levodopa clearance, and there is a need for lower continuous maintenance doses, regardless of patients’ COMT genotype.

The interactive effect of genetic polymorphisms of IL-10 and COMT on cognitive function in schizophrenia

Dopaminergic and inflammatory systems have been proven to play an important role in the cognitive deficits of schizophrenia. Although increasing evidence indicates two systems have strong interaction, the relevant research on this interaction is still limited. Catechol-o-methyltransferase (COMT) and Interleukin-10 (IL-10) play critical functions in dopaminergic and inflammatory systems respectively, and their genetic polymorphisms are both associated with cognitive function. However, the interactive effect of their genetic polymorphisms has not been investigated. In this study, COMT Val158Met (rs4680) and IL-10 -592A/C (rs1800872) polymorphisms were measured in patients with chronic schizophrenia (n = 244) and healthy controls (n = 396), and their cognitive functions were assessed using the “Repeatable Battery for the Assessment of Neuropsychological Status” (RBANS). We found that IL-10 alone had no effect on cognitive function, while COMT affected language ability and interacted with the schizophrenia (case vs control) or sex in multiple RBANS indexes. Additionally, we found there was a significant interactive effect between IL-10 and COMT polymorphisms on multiple cognitive indexes of RBANS. In detail, the analysis showed that the IL-10 polymorphism had opposite effects on cognitive function in different COMT genotype carriers; meanwhile, the polymorphism of COMT only had a significant effect on cognitive function in IL-10 C carriers. And this interaction was more significant in schizophrenia than in controls. Our study discovered for the first time, there is an interactive effect between IL-10 and COMT genetic polymorphisms on cognitive function, which is valuable for further investigations and drug administrations associated with both systems.

COMT Genotype and Efficacy of Propranolol for TMD Pain: A Randomized Trial

Propranolol is a nonselective β-adrenergic receptor antagonist that is efficacious in reducing facial pain. There is evidence that its analgesic efficacy might be modified by variants of the catechol-O-methyltransferase (COMT) gene. We tested the hypothesis in a subset of 143 non-Hispanic Whites from a randomized controlled trial of patients with painful temporomandibular disorder (TMD). Patients were genotyped for rs4680, a single nucleotide polymorphism of COMT, and randomly allocated to either propranolol 60 mg twice daily or placebo. During the 9-wk follow-up period, patients recorded daily ratings of facial pain intensity and duration; the product was computed as an index of facial pain. Postbaseline change in the index at week 9 (the primary endpoint) was analyzed as a continuous variable and dichotomized at thresholds of ≥30% and ≥50% reduction. Mixed models for repeated measures tested for the genotype × treatment group interaction and estimated means, odds ratios (ORs), and 95% confidence limits (95% CLs) of efficacy within COMT genotypes assuming an additive genetic model. In secondary analysis, the cumulative response curves were plotted for dichotomized reductions ranging from ≥20% to ≥70%, and genotype differences in area under the curve percentages (%AUC) were calculated to signify efficacy. Mean index reduction did not differ significantly (P = 0.277) according to genotype, whereas the dichotomized ≥30% reduction revealed greater efficacy among G:G homozygotes (OR = 10.9, 95%CL = 2.4, 50.7) than among A:A homozygotes (OR = 0.8, 95%CL = 0.2, 3.2) with statistically significant interaction (P = 0.035). Cumulative response curves confirmed greater (P = 0.003) efficacy for G:G homozygotes (%AUC difference = 43.7, 95%CL = 15.4, 72.1) than for A:A homozygotes (%AUC difference = 6.5, 95%CL = -30.2, 43.2). The observed antagonistic effect of the A allele on propranolol’s efficacy was opposite the synergistic effect hypothesized a priori. This unexpected result highlights the need for better knowledge of COMT’s role in pain pathogenesis if the gene is to be used for precision-medicine treatment of TMD (ClinicalTrials.gov NCT02437383).

Effects of childhood trauma experience and COMT Val158Met polymorphism on brain connectivity in a multimodal MRI study.

Childhood adversity may act as a stressor to produce a cascade of neurobiological effects that irreversibly alter neural development, setting the stage for developing psychopathology in adulthood. The catechol‐O‐methyltransferase (COMT) Val158Met polymorphism has received much attention as a candidate gene associated with environmental adversity, modifying risk for psychopathology. In this study, we aim to see how gene × brain × environment models give a more integrative understanding of brain modifications that contribute to predicting psychopathology related to childhood adversity. A large nonclinical sample of young adults completed Childhood Trauma Questionnaire (CTQ), behavioral scores, multimodal magnetic resonance imaging (MRI) scans, and genotyping. We utilized graph‐based connectivity analysis in morphometric similarity mapping and resting‐state functional MRI to investigate brain alterations. Relationships among COMT genotypes, CTQ score, imaging phenotypes, and behavioral scores were identified by multiple regression and mediation effect analysis. Significant main effect of CTQ score was found in anatomic connectivity of orbitofrontal cortex that was an outstanding mediator supporting the relationship between CTQ score and anxiety/harm‐avoiding personality. We also noted the main effect of childhood trauma on reorganization of functional connectivity within the language network. Additionally, we found genotype × CTQ score interactions on functional connectivity of the right frontoparietal network as well as anatomic connectivity of motor and limbic regions. Our data demonstrate childhood adversity and COMT genotypes are associated with abnormal brain connectivity, structurally and functionally. Early identification of individuals at risk, assessment of brain abnormality, and cognitive interventions may help to prevent or limit negative outcomes.

Catechol-O-methyltransferase genotype differentially contributes to the flexibility and stability of cognitive sets in patients with psychotic disorders and their first-degree relatives

Dopaminergic activity in prefrontal cortex is modulated by the low (Met) and high (Val) activity of the rs4680 Val158Met single nucleotide polymorphism (SNP) in the Catechol-O-Methyltransferase (COMT) gene. While this has been related to working memory maintenance in patients with schizophrenia, the familial pattern, impact across the psychosis spectrum, and the role of this genotype on other aspects of behavior, such as cognitive flexibility, remains unclear. The relationship between COMT Val158Met genotype and both cognitive stability and flexibility were assessed using the Penn Conditional Exclusion Test (PCET) in healthy controls (n = 241), patients with psychotic disorders (n = 542), and their first-degree relatives (n = 613) from the Bipolar-Schizophrenia Network on Intermediate Phenotypes (B-SNIP) consortium. Higher rates of perseverative errors (poor flexibility) were associated with the low-activity COMT genotype (Met allele carriers) in probands compared to their first-degree relatives with the same genotype. Probands and first-degree relatives homozygous for the high-activity COMT enzyme (Val/Val) showed elevated rates of regressive errors (poor stability) compared to controls. Conversely, heterozygous relatives had comparable regressive error rates to controls, with probands showing elevated errors in comparison. These findings suggest that impaired suppression of learned response patterns and reduced stability of mental sets may be a familial intermediate cognitive phenotype related to Val COMT allele genotype.

Interaction of Catechol-O-methyltransferase Val158 Met polymorphism and sex influences association of parietal intrinsic functional connectivity and immediate verbal memory.

IntroductionSex differences modulate catechol‐O‐methyltransferase (COMT) genotype effect at a synaptic dopamine level, which influences brain function as well as cognitive performance. In this study, we investigated how COMT Val158Met polymorphism and sex affect intrinsic functional connectivity and memory.MethodsIntrinsic functional networks were extracted using independent component analysis of resting‐state functional magnetic resonance imaging data from 186 healthy young COMT‐genotyped participants. The association of these functional networks and memory function was tested to investigate whether the effect of COMT × sex interaction influences the association of intrinsic functional connectivity and memory performance. Quadratic curve fit estimation was used to examine the relationship between functional connectivity and speculative dopamine level among groups.ResultsCOMT MM/MV carriers, relative to VV carriers, showed increased functional connectivity in left superior parietal lobule and right inferior frontal gyrus. Further, male MM/MV carriers showed significant higher mean functional connectivity in left inferior parietal lobule relative to male VV carriers and female MM/MV carriers, which was associated with worse immediate verbal recall performance. Additionally, the relationship between inferior parietal lobule functional connectivity and speculative dopamine level among groups fits the quadratic curve.ConclusionsThese findings suggest that the interaction of COMT genotype and sex might regulate synaptic dopaminergic concentrations and influence the association of intrinsic functional connectivity and immediate verbal memory in left inferior parietal lobule.

Gene polymorphisms and motor levodopa-induced complications in Parkinson's disease.

ObjectiveThe aim of the study was to evaluate the association of individual and combined single‐nucleotide polymorphisms in brain‐derived neurotrophic factor (BDNF), dopamine transporter (DAT), and catechol‐O‐methyltransferase (COMT) genes with the occurrence of motor levodopa‐induced complications (MLIC) in Parkinson's disease (PD).Materials and MethodsWe studied 76 patients with PD (MLIC occurred in 56.6%) and 60 controls. Allelic discrimination of rs6265 BDNF (Val66Met), rs397595 DAT (SLC6A3), and rs4680 COMT (Val158Met) genes were genotyped. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated using multinominal logistic regression. Orthogonal partial least squares (OPLS) analysis and OPLS discriminant analysis (OPLS‐DA) were used to analyze qualitative genetic data.ResultsThe risk of PD in subjects with the AG BDNF genotype was increased sixfold (OR = 6.12, 95% CI = 2.88–13.02, p < .0001), and AG BDNF and AG DAT genotypes were correlated with PD in OPLS‐DA (VIP > 1). There were no differences in distributions of BDNF, DAT and COMT genotypes between PD groups with and without MLIC, while OPLS model showed that genotype combination of AG BDNF, AG DAT, and GG COMT was correlated with MLIC and genotypes combination of GG BDNF, AA DAT, and AA COMT with lack of MLIC in PD patients (VIP > 1).ConclusionsOur results confirmed the association of rs6265 BDNF (Val66Met) with the risk of PD and suggest a synergic effect of rs6265 BDNF (Val66Met), rs397595 DAT (SLC6A3), and rs4680 COMT (Val158Met) polymorphisms on the occurrence of MLIC.

Associations between catechol-O-methyltransferase (COMT) genotypes at rs4818 and rs4680 and gene expression in human dorsolateral prefrontal cortex.

Having reported associations between catechol-O-methyltransferase (COMT) genotypes at SNPs rs4818 and rs4680 with levels of soluble COMT (S-COMT) in human dorsolateral prefrontal cortex (DLPFC), we postulated that changes in the levels of cortical S-COMT could impact on behavioural abilities associated with COMT genotype through S-COMT-mediated changes in gene expression. To test this hypothesis, we have examined the relationships between COMT genotypes and gene expression measured using the Affymetrix™ Human Exon 1.0 ST Array in the DLPFC from 141 individuals, some of whom had had a psychiatric disorder. There were significant differences in levels of expression of 15 genes between individuals with a homozygous genotype at rs4818 (GG vs CC), compared to differences in levels of expression of 6 genes between homozygotes at rs4680 (GG vs AA); levels of expression of CEP128, EFCAB13, and FAM133A differed between homozygotes at both SNPs. Fourteen of the genes differentially expressed in the DLPFC according to COMT genotypes have oestrogen receptor elements and their expression could, therefore, be regulated by catecholestrogens, which are substrates for COMT that occupy and activate oestrogen receptors. In addition, the changes in gene expression between the homozygotes at rs4818 or rs4680 would be expected to impact on neuronal function, synaptic plasticity, cognition, and attention. These data would support a hypothesis that the mechanism underlying the association between COMT genotype and cognition involves differential changes in cortical gene expression.

Genetic modulation of facial emotion recognition in borderline personality disorder

Facial emotion recognition (FER) has been described to be impaired in borderline personality disorder (BPD), especially for neutral faces. Genetic modulation of FER has been studied in healthy individuals and some psychiatric conditions, but no genetic association studies have been conducted in BPD hitherto. The main objective of our study was to explore the influence of the serotonin-transporter-linked promoter region (5HTTLPR) and catechol-o-methyltransferase (COMT) Val158Met on facial emotion processing among BPD patients. To that end, seventy-six BPD outpatients were asked to complete a computer-based facial affect recognition task, representing four emotions (neutral, happy, fearful or angry). Accuracy of FER and perceptual biases were calculated. The 5HTTLPR and COMT Val158Met polymorphisms were genotyped using saliva samples. Individuals with the high-activity serotonin-transporter genotype and those with the low-activity COMT genotype had significantly more difficulties identifying neutral faces; the former showed stronger bias to perceive neutral faces as happy, and the latter, neutral faces as fearful. Interestingly, the perceptual biases observed in our patients are similar to previous reports in healthy individuals. The authors propose that the ability to accurately recognize neutral faces might be a possible endophenotype of BPD. Sex-genotype interactions were also observed in relation to angry faces and 5HTTLPR, and neutral faces and COMT Val158Met polymorphisms, in line with sex-related differences previously described for both polymorphisms in relation to FER and other cognitive and behavioral outcomes. The impact of inaccurate FER on psychosocial functioning and potential interventions are also discussed.