High-activity variants of the uMAOA polymorphism increase the risk for depression in a large primary care sample

Association between serum catecholamine levels and VNTR polymorphism in the promoter region of the monoamine oxidase A gene in forensic autopsy cases

Monoamine oxidase A (MAOA) catalyzes oxidative deamination of catecholamines. A functional variable number tandem repeat (VNTR) polymorphism in the promoter region of the MAOA gene has been previously reported. In the present study, we measured serum adrenaline (Adr), noradrenaline (Nad), and dopamine (DA) levels in 90 male and 34 female Japanese autopsy cases in which amphetamines or psychotropic drugs were not detected.We examined the frequencies of MAOA-uVNTR alleles in these cases and investigated the effects of the MAOA-uVNTR polymorphism on serum Adr, Nad, and DA levels. Evaluation indicated no significant association between MAOA-uVNTR polymorphism and serum Adr, Nad, or DA levels in males, although a significant association between MAOA-uVNTR polymorphism and serum Adr and DA levels were observed in females. Females with the 3/3 genotype had higher serum Adr and DA levels than those with a 4-repeat allele (3/4 and 4/4 genotypes) (p = 0.048 and 0.020, respectively). There was no significant association between MAOA-uVNTR polymorphism and serum Nad levels in females. The present study indicates that MAOA-uVNTR polymorphism influences serum Adr and DA levels only in females.

MAOA uVNTR Polymorphism Influence on Older Adults Diagnosed with Diabetes Mellitus/Systemic Arterial Hypertension

Background

Monoamine oxidase (MAO) is involved in several biological processes associated with well-being and mental health, and alterations in its function might directly impact various mental disorders. Some mental disorders concomitantly occur in individuals with clinical characteristics, such as substance abuse and diabetes.

Objective

To analyze the functional MAOA uVNTR polymorphism genotype frequency in an older adult population with diabetes mellitus/arterial hypertension and associate this frequency with clinical characteristics impacting daily life. Methodology. Older adults diagnosed with diabetes mellitus, systemic arterial hypertension, or both (DM/SAH) were selected and had their MAOA gene genotyped for uVNTR polymorphism. The revised Beck Depression Inventory (BDI) and a questionnaire were also applied to determine their mental health and clinical characteristics.

Results

The allelic variants detected among the participants were the 2R, 3R, 4R, and 3R/4R heterozygous genotypes. Genotypes solely containing the 3R allele had patients who marked yes for smoking and alcoholism, and only those with the 3R genotypes (female 3R/3R homozygote or male 3R∗ hemizygote) were significant. Although not statistically significant, only 3R and 3R/4R genotypes presented cases of severe depression per the revised BDI interpretations.

Conclusion

The MAOA uVNTR polymorphism's low-activity 3R allele presence in an older adult population diagnosed with DM/SAH may represent a risk for developing substance use (alcohol and smoking) dependence.

Gene Therapy for Neuropsychiatric Disorders: Potential Targets and Tools

Neuropsychiatric disorders that affect the central nervous system cause considerable pressures on the health care system and have a substantial economic burden on modern societies. The present treatments based on available drugs are mostly ineffective and often costly. The molecular process of neuropsychiatric disorders is closely connected to modifying the genetic structures inherited or caused by damage, toxic chemicals, and some current diseases. Gene therapy is presently an experimental concept for neurological disorders. Clinical applications endeavor to alleviate the symptoms, reduce disease progression, and repair defective genes. Implementing gene therapy in inherited and acquired neurological illnesses entails the integration of several scientific disciplines, including virology, neurology, neurosurgery, molecular genetics, and immunology. Genetic manipulation has the power to minimize or cure illness by inducing genetic alterations at endogenous loci. Gene therapy that involves treating the disease by deleting, silencing, or editing defective genes and delivering genetic material to produce therapeutic molecules has excellent potential as a novel approach for treating neuropsychiatric disorders. With the recent advances in gene selection and vector design quality in targeted treatments, gene therapy could be an effective approach. This review article will investigate and report the newest and the most critical molecules and factors in neuropsychiatric disorder gene therapy. Different genome editing techniques available will be evaluated, and the review will highlight preclinical research of genome editing for neuropsychiatric disorders while also evaluating current limitations and potential strategies to overcome genome editing advancements.

MAOA uVNTR Genetic Variant and Major Depressive Disorder: A Systematic Review

Major Depressive Disorder (MDD) is a highly prevalent multifactorial psychopathology affected by neurotransmitter levels. Monoamine Oxidase A (MAOA) influences several neural pathways by modulating these levels. This systematic review (per PRISMA protocol and PECOS strategy) endeavors to understand the MAOA uVNTR polymorphism influence on MDD and evaluate its 3R/3R and 3R* genotypic frequencies fluctuation in MDD patients from different populations. We searched the Web of Science, PubMed, Virtual Health Library, and EMBASE databases for eligible original articles that brought data on genotypic frequencies related to the MAOA uVNTR variant in patients with MDD. We excluded studies with incomplete data (including statistical data), reviews, meta-analyses, and abstracts. Initially, we found 43 articles. After removing duplicates and applying the inclusion/exclusion criteria, seven articles remained. The population samples studied were predominantly Asians, with high 3R and 4R allele frequencies. Notably, we observed higher 3R/3R (female) and 3R* (male) genotype frequencies in the healthy control groups and higher 4R/4R (female) and 4R* (male) genotype frequencies in the MDD groups in the majority of different populations. Despite some similarities in the articles analyzed, there is still no consensus on the MAOA uVNTR variant’s role in MDD pathogenesis.

A comprehensive review of monoamine oxidase inhibitors as Anti-Alzheimer's disease agents: A review

Monoamine oxidases (MAO-A and MAO-B) are mammalian flavoenzyme, which catalyze the oxidative deamination of several neurotransmitters like norepinephrine, dopamine, tyramine, serotonin, and some other amines. The oxidative deamination produces several harmful side products like ammonia, peroxides, and aldehydes during the biochemical reaction. The concentration of biochemical neurotransmitter alteration in the brain by MAO is directly related with several neurological disorders like Alzheimer's disease and Parkinson's disease (PD). Activated MAO also contributes to the amyloid beta (Aβ) aggregation by two successive cleft β-secretase and γ-secretase of amyloid precursor protein (APP). Additionally, activated MAO is also involved in aggregation of neurofibrillary tangles and cognitive destruction through the cholinergic neuronal damage and disorder of the cholinergic system. MAO inhibition has general anti-Alzheimer's disease effect as a consequence of oxidative stress reduction prompted by MAO enzymes. In this review, we outlined and addressed recent understanding on MAO enzymes such as their structure, physiological function, catalytic mechanism, and possible therapeutic goals in AD. In addition, it also highlights the current development and discovery of potential MAO inhibitors (MAOIs) from various chemical scaffolds.

Alternative splicing in serotonergic system: Implications in neuropsychiatric disorders

BACKGROUND

The serotonergic system is a key component of physiological brain function and is essential for proper neurological activity. Numerous neuropsychiatric disorders are associated with deregulation of the serotonergic system. Accordingly, many pharmacological treatments are focused on modulation of this system. While providing a promising line of therapeutic moderation, these approaches may be complicated due to the presence of alternative splicing events for key genes in this pathway. Alternative splicing is a co-transcriptional process by which different mRNA transcripts can be produced from the same gene. These different isoforms may have diverse activities and functions, and their relative balance is often critical for the maintenance of homeostasis. Alternative splicing greatly increases the production of proteins, augmenting cell plasticity, and provides an important control point for regulation of gene expression.

AIM

The objective of this narrative review is to discuss the potential impact of alternative splicing of different components of the serotonergic system and speculate on their involvement in several neuropsychiatric disorders.

CONCLUSIONS

The specific role of each isoform in disease and their relative activities in the signalling pathways involved are yet to be determined. We need to gain a better understanding of the basis of alternative isoforms of the serotonergic system in order to fully understand their impact and be able to develop new effective pharmacological isoform-specific targets.

Emotional stability is associated with the MAOA promoter uVNTR polymorphism in women

BACKGROUND

Neuroticism is associated with low emotional stability, and it is characterized by a tendency to perceive ordinary situations as threatening and difficult to manage. This personality trait has been associated with psychological distress and predicts some mental disorders. Previous studies have shown that women tend to be more neurotic than men and, in general, females have also a higher incidence of anxious and depressive disorders.

METHODS

We analyzed in a sample of 99 female university students (from 18 to 26 years old) if emotional stability, measured using the Big Five Questionnaire, was linked to polymorphic variants in candidate genes related to dopaminergic and serotonergic systems, and other personality variables.

RESULTS

We found that emotional stability and its subdimensions are genetically associated with MAOA-uVNTR polymorphism. Thus, women carriers of the 3-repeat allele (lower MAO-A expression) showed higher levels of emotional stability. No associations were found with other polymorphisms analyzed, including COMT Val¹⁵⁸ Met, 5-HTTLPR, and DAT 3'UTR VNTR. Furthermore, our results showed a negative correlation between emotional stability and depression, state anxiety, and trait anxiety. In fact, MAOA-uVNTR and trait anxiety also explained emotional stability and its subdimensions. We also found that other genetic characteristic, phenylthiocarbamide tasting, explained impulsivity, specifically tasters controlled impulses better than nontasters.

CONCLUSION

Our results indicate that neuroticism might be regulated by MAOA and could be a common factor between different phenotypes, such as aggressive behaviors or personality disorders, observed in women with higher activity genotype who had been exposed to negative environments during childhood. This study could lead to a better understanding of the basis of emotional stability and could lead to future projects for this purpose.

Structure-Based Specific Detection and Inhibition of Monoamine Oxidases and Their Applications in Central Nervous System Diseases

Monoamine oxidases (MAOs) are the enzymes that catalyze the oxidation of monoamines, such as dopamine, norepinephrine, and serotonin, which serve as key neurotransmitters in the central nervous system (CNS). MAOs play important roles in maintaining the homeostasis of monoamines, and the aberrant expression or activation of MAOs underlies the pathogenesis of monoamine neurotransmitter disorders, including neuropsychiatric and neurodegenerative diseases. Clearly, detecting and inhibiting the activities of MAOs is of great value for the diagnosis and therapeutics of these diseases. Accordingly, many specific detection probes and inhibitors have been developed and substantially contributed to basic and clinical studies of these diseases. In this review, progress in the detecting and inhibiting of MAOs and their applications in mechanism exploration and treatment of neurotransmitter-related disorders is summarized. Notably, how the detection probes and inhibitors of MAOs were developed has been specifically addressed. It is hoped that this review will benefit the design of more effective and sensitive probes and inhibitors for MAOs, and eventually the treatment of monoamine neurotransmitter disorders.

The interaction between monoamine oxidase A (MAOA) and childhood maltreatment as a predictor of personality pathology in females: Emotional reactivity as a potential mediating mechanism

Research consistently demonstrates that common polymorphic variation in monoamine oxidase A (MAOA) moderates the influence of childhood maltreatment on later antisocial behavior, with growing evidence that the "risk" allele (high vs. low activity) differs for females. However, little is known about how this Gene × Environment interaction functions to increase risk, or if this risk pathway is specific to antisocial behavior. Using a prospectively assessed, longitudinal sample of females (n = 2,004), we examined whether changes in emotional reactivity (ER) during adolescence mediated associations between this Gene × Environment and antisocial personality disorder in early adulthood. In addition, we assessed whether this putative risk pathway also conferred risk for borderline personality disorder, a related disorder characterized by high ER. While direct associations between early maltreatment and later personality pathology did not vary by genotype, there was a significant difference in the indirect path via ER during adolescence. Consistent with hypotheses, females with high-activity MAOA genotype who experienced early maltreatment had greater increases in ER during adolescence, and higher levels of ER predicted both antisocial personality disorder and borderline personality disorder symptom severity. Taken together, findings suggest that the interaction between MAOA and early maltreatment places women at risk for a broader range of personality pathology via effects on ER.

Sex differences modulating serotonergic polymorphisms implicated in the mechanistic pathways of risk for depression and related disorders

Despite consistent observations of sex differences in depression and related emotional disorders, we do not yet know how these sex differences modulate the effects of genetic polymorphisms implicated in risk for these disorders. This Mini-Review focuses on genetic polymorphisms of the serotonergic system to illustrate how sex differences might modulate the neurobiological pathways involved in the development of depression. We consider the interacting role of environmental factors such as early-life stress. Given limited current knowledge about this topic, we highlight methodological considerations, challenges, and guidelines for future research. © 2016 Wiley Periodicals, Inc.

Biological hypotheses and biomarkers of bipolar disorder

The most common mood disorders are major depressive disorders and bipolar disorders (BD). The pathophysiology of BD is complex, multifactorial, and not fully understood. Creation of new hypotheses in the field gives impetus for studies and for finding new biomarkers for BD. Conversely, new biomarkers facilitate not only diagnosis of a disorder and monitoring of biological effects of treatment, but also formulation of new hypotheses about the causes and pathophysiology of the BD. BD is characterized by multiple associations between disturbed brain development, neuroplasticity, and chronobiology, caused by: genetic and environmental factors; defects in apoptotic, immune-inflammatory, neurotransmitter, neurotrophin, and calcium-signaling pathways; oxidative and nitrosative stress; cellular bioenergetics; and membrane or vesicular transport. Current biological hypotheses of BD are summarized, including related pathophysiological processes and key biomarkers, which have been associated with changes in genetics, systems of neurotransmitter and neurotrophic factors, neuroinflammation, autoimmunity, cytokines, stress axis activity, chronobiology, oxidative stress, and mitochondrial dysfunctions. Here we also discuss the therapeutic hypotheses and mechanisms of the switch between depressive and manic state.

The role of MAO in personality and drug use

Monoamine oxidases, both MAO-A and MAO-B, have been implicated in personality traits and complex behaviour, including drug use. Findings supporting the involvement of MAO-A and MAO-B in shaping personality and in the development of strategies of making behavioural choices come from a variety of studies that have examined either prevalence of gene variants in clinical groups or population-derived samples, estimates of enzyme activity in blood or, by positron emission tomography, in the brain and, most recently, measurement of methylation of the gene. Most of the studies converge in associating MAO-A and MAO-B with impulsive, aggressive or antisocial personality traits or behaviours, including alcohol-related problems, and for MAO-A available evidence strongly supports interaction with adverse environmental exposures in childhood. What is known about genotype effects, and on expression and activity of the enzyme in the brain and in blood has not yet been possible to unite into a mechanistic model of the role of monoamine systems, but the reason for this low degree of generalization is likely caused by the cross-sectional nature of investigation that has not incorporated the developmental effects of MAO-s in critical time windows, including the foetal period. The "risk variants" of both MAO-s appear to increase behavioural plasticity, as supportive environments may particularly well enhance the hidden potential of their carriers. Importantly, male and female brain and behaviours have been found very different with regard to MAO×life events interaction. Future studies need to take into consideration these developmental aspects and sex/gender, as well as to specify the role of different types of environmental factors.

Drugs related to monoamine oxidase activity

Progress in understanding the role of monoamine neurotransmission in pathophysiology of neuropsychiatric disorders was made after the discovery of the mechanisms of action of psychoactive drugs, including monoamine oxidase (MAO) inhibitors. The increase in monoamine neurotransmitter availability, decrease in hydrogen peroxide production, and neuroprotective effects evoked by MAO inhibitors represent an important approach in the development of new drugs for the treatment of mental disorders and neurodegenerative diseases. New drugs are synthesized by acting as multitarget-directed ligands, with MAO, acetylcholinesterase, and iron chelation as targets. Basic information is summarized in this paper about the drug-induced regulation of monoaminergic systems in the brain, with a focus on MAO inhibition. Desirable effects of MAO inhibition include increased availability of monoamine neurotransmitters, decreased oxidative stress, decreased formation of neurotoxins, induction of pro-survival genes and antiapoptotic factors, and improved mitochondrial functions.

Does refining the phenotype improve replication rates? A review and replication of candidate gene studies on Major Depressive Disorder and Chronic Major Depressive Disorder

Replication has been poor for previously reported candidate genes involved in Major Depressive Disorder (MDD). One possible reason is phenotypic and genetic heterogeneity. The present study replicated genetic associations with MDD as defined in DSM-IV and with a more narrowly defined MDD subtype with a chronic and severe course. We first conducted a systematic review of genetic association studies on MDD published between September 2007 and June 2012 to identify all reported candidate genes. Genetic associations were then tested for all identified single nucleotide polymorphisms (SNPs) and the entire genes using data from the GAIN genome-wide association study (MDD: n = 1,352; chronic MDD subsample: n = 225; controls: n =  1,649). The 1,000 Genomes database was used as reference for imputation. From 157 studies identified inthe literature, 81 studies reported significant associations with MDD, involving 245 polymorphisms in 97 candidate genes, from which we were able to investigate 185 SNPs in 89 genes. We replicated nine candidate SNPs in eight genes for MDD and six in five genes for chronic MDD. However, these were not more than expected by chance. At gene level, we replicated 18 genes for MDD and 17 genes for chronic MDD, both significantly more than expected by chance. We showed that replication rates were improved for MDD compared to a previous, highly similar, replication study based on studies published before 2007. Effect sizes of the SNPs and replication rates of the candidate genes were improved in the chronic subsample compared to the full sample. Nonetheless, replication rates were still poor.

The MAOA, COMT, MTHFR and ESR1 gene polymorphisms are associated with the risk of depression in menopausal women

OBJECTIVE

The aim of the study was assessment of a possible relationship between the polymorphisms of the candidate genes participating in the etiology of some neurological and psychiatric disorders and the risk of depression in perimenopausal and postmenopausal women.

METHODS

A total of 167 (54 perimenopausal and 113 postmenopausal) Caucasian women from western Poland, aged 42-67, were recruited as the patient group in the study because of depressive symptoms, and another 321 healthy women (102 perimenopausal and 219 postmenopausal) served as the controls. All study participants were evaluated for climacteric and depressive disorders according to the Kupperman index and Hamilton rating scale for depression (HRSD), respectively. The following candidate genes were selected for the study: 5HTR2A, 5HTR1B, 5HTR2C, TPH1, TPH2, MAOA, COMT, NET, GABRB1, ESR1, MTHFR, MTR and MTHFD1. In each group the frequencies of the polymorphisms were determined using PCR-RFLP analysis.

RESULTS

After correcting for Bonferroni multiple tests, we found associations between the MAOA c.1460C>T (SNP 1137070), COMT c.472G>A (SNP 4680), MTHFR c.677C>T (SNP 1801133) and ESR1 454(-351) A>G (SNP 9340799) polymorphisms to mild and moderate depressive symptoms in menopausal women. In the perimenopausal and postmenopausal women, genotype association of the MAOA c.1460 CT and c.1460 CT+TT (OR=1.83; pcorr=0.009 and OR=1.85; pcorr=0.003, resp.), and of the MTHFR c.677 TT and c.677 CT+TT (OR=3.52; pcorr=0.00009 and OR=2.06; pcorr=0.0006, resp.), as well as of the COMT c.472 GA and COMT c.472 GA+AA genotypes (OR=2.23; pcorr=0.03 and OR=2.17; pcorr=0.027, resp.) in the postmenopausal women revealed significantly higher frequencies of these variants in depressed female patients than in controls, whereas the ESR1 454(-351) AG and 454(-351) AG+GG genotypes were associated with lower risk of depression in postmenopausal women (OR=0.48; pcorr=0.012, and OR=0.52; pcorr=0.015, resp.).

CONCLUSIONS

Our study substantiates the involvement of the MAOA and MTHFR polymorphisms in climacteric depression and offers evidence that the COMT and ESR1 genes may also play a role in the susceptibility to depressive mood in postmenopausal women.

MAOA Variants and Genetic Susceptibility to Major Psychiatric Disorders

Monoamine oxidase A (MAOA) is a mitochondrial enzyme involved in the metabolism of several biological amines such as dopamine, norepinephrine, and serotonin, which are important neurochemicals in the pathogenesis of major psychiatric illnesses. MAOA is regarded as a functional plausible susceptibility gene for psychiatric disorders, whereas previous hypothesis-driven association studies obtained controversial results, a reflection of small sample size, genetic heterogeneity, or true negative associations. In addition, MAOA is not analyzed in most of genome-wide association studies (GWAS) on psychiatric disorders, since it is located on Chromosome Xp11.3. Therefore, the effects of MAOA variants on genetic predisposition to psychiatric disorders remain obscure. To fill this gap, we collected psychiatric phenotypic (schizophrenia, bipolar disorder, and major depressive disorder) and genetic data in up to 18,824 individuals from diverse ethnic groups. We employed classical fixed (or random) effects inverse variance weighted methods to calculate summary odds ratios (OR) and 95 % confidence intervals (CI). We identified a synonymous SNP rs1137070 showing significant associations with major depressive disorder (p = 0.00067, OR = 1.263 for T allele) and schizophrenia (p = 0.0039, OR = 1.225 for T allele) as well as a broad spectrum of psychiatric phenotype (p = 0.000066, OR = 1.218 for T allele) in both males and females. The effect size was similar between different ethnic populations and different gender groups. Collectively, we confirmed that MAOA is a risk gene for psychiatric disorders, and our results provide useful information toward a better understanding of genetic mechanism involving MAOA underlying risk of complex psychiatric disorders.

Association study of monoamine oxidase-A gene promoter polymorphism (MAOA-uVNTR) with self-reported anxiety and other psychopathological symptoms in a community sample of early adolescents

The polymorphism upstream of the gene for monoamine oxidase A (MAOA-uVNTR) is reported to be an important enzyme involved in human physiology and behavior. With a sample of 228 early-adolescents from a community sample (143 girls) and adjusting for environmental variables, we examined the influence of MAOA-uVNTR alleles on the scores obtained in the Screen for Childhood Anxiety and Related Emotional Disorders and in the Child Symptom Inventory-4. Our results showed that girls with the high-activity MAOA allele had higher scores for generalized and total anxiety than their low-activity peers, whereas boys with the low-activity allele had higher social phobia scores than boys with the high-activity allele. Results for conduct disorder symptoms did not show a significant relationship between the MAOA alleles and the presence of these symptoms. Our findings support a possible association, depending on gender, between the MAOA-uVNTR polymorphism and psychopathological disorders such as anxiety, which affects high rates of children and adolescents.

An analysis of the influence of selected genetic and hormonal factors on the occurrence of depressive symptoms in late-reproductive-age women

BACKGROUND

The aim of this study was to analyze the influence of genetic and hormonal factors on incidences of depressive symptoms in late-reproductive-age women.

METHODS

The study was performed using the Beck Depression Inventory, the PCR, and genetic tests of 347 healthy late-reproductive-age Polish women.

RESULTS

The relationship between the level of anti-Müllerian hormone (AMH) and depressive symptoms was not statistically significant (p > 0.05). Increases in age and FSH levels were accompanied by a decrease in AMH level in a significant way (p < 0.05). There were no statistically significant relationships between the distribution of genotypes and the frequency of alleles of the investigated polymorphisms and depressive symptoms according to the Beck Depression Inventory.

CONCLUSIONS

(1) The presence of the s/s genotype of the 5-HTTLPR polymorphism in the serotonin transporter promoter region and the 3/3 genotype of the 30-bp VNTR polymorphism in the monoamine oxidase A promoter region does not contribute to the development of depressive symptoms in late-reproductive-age women. (2) A relationship between the level of anti-Müllerian hormone and depressive symptoms was not confirmed in the group of healthy late-reproductive-age women. (3) AMH level correlates negatively with FSH level and age, which confirms that AMH can be regarded as a factor reflecting the ovarian reserve.

Modulation of monoamine oxidase (MAO) expression in neuropsychiatric disorders: genetic and environmental factors involved in type A MAO expression

Monoamine oxidase types A and B (MAO-A, MAO-B) regulate the levels of monoamine neurotransmitters in the brain, and their dysfunction may be involved in the pathogenesis and influence the clinical phenotypes of neuropsychiatric disorders. Reversible MAO-A inhibitors, such as moclobemide and befloxatone, are currently employed in the treatment of emotional disorders by inhibiting the enzymatic degradation of dopamine, serotonin and norepinephrine in the central nervous system (CNS). It has been suggested that the irreversible MAO-B inhibitors selegiline and rasagiline exert a neuroprotective effect in Parkinson's and Alzheimer's diseases. This effect, however, is not related to their inhibition of MAO activity; in animal and cellular models, selegiline and rasagiline protect neuronal cells through their anti-apoptotic activity and induction of pro-survival genes. There is increasing evidence that MAO-A activity, but not that of MAO-B, is implicated in the pathophysiology of neurodegenerative disorders, but also in gene induction by MAO-B inhibitors; on the other hand, selegiline and rasagiline increase MAO-A mRNA, protein, and enzyme activity levels. Taken together, these results suggest that each MAO subtype exerts effects that modulate the expression and activity of the other isoenzyme. The roles of MAO-A and -B in the CNS should therefore be re-evaluated with respect to the "type-specificity" of their inhibitors, which may not be unconditional during chronic treatment. Mao-a expression, in particular, may be implicated in pathogenesis and phenotypes in neuropsychiatric disorders. MAO-A expression is modified by mao polymorphisms affecting its transcriptional efficiency, as well as by mutations and polymorphism of parkin, Sirt1, FOXO, microRNA, presenilin-1, and other regulatory proteins. In addition, childhood maltreatment has been shown to have an impact upon adolescent social behavior in children with mao-a polymorphisms of low transcriptional activity. Low MAO-A activity may increase the levels of serotonin and norepinephrine, resulting in disturbed neurotransmitter system development and behavior. This review discusses genetic and environmental factors involved in the regulation of MAO-A expression, in the contexts of neuropsychiatric function and of the regulation of neuronal survival and death.

Mitigating aggressiveness through education? The monoamine oxidase A genotype and mental health in general population

OBJECTIVE

Monoamine oxidase A (MAOA) gene promoter region includes a variable number of tandem repeat (VNTR) associated with antisocial behaviour in adverse environment. We have examined the effect of the MAOA-uVNTR on mental health and academic success by using a population representative sample and a longitudinal design.

METHODS

The data of the older cohort (n = 593, aged 15 years at the original sampling) of the longitudinal Estonian Children Personality, Behaviour and Health Study (ECPBHS) were used. Follow-ups were conducted at ages 18 and 25 years. Aggressiveness, inattention and hyperactivity were reported by class teachers or, at older age, self-reported. Stressful life events, psychological environment in the family and interactions between family members were self-reported. Data of general mental abilities and education were obtained at the age of 25, and lifetime psychiatric disorder assessment was carried out with the Mini-International Neuropsychiatric Interview (MINI) interview.

RESULTS

MAOA-uVNTR genotype had no independent effect on aggressiveness, hyperactive and inattentive symptoms, and neither was there a genotype interaction with adverse life events. Interestingly, the proportion of male subjects with higher education by the age of 25 was significantly larger among those with MAOA low-activity alleles (χ² = 7.13; p = 0.008). Logistic regression revealed that MAOA low-activity alleles, higher mental abilities, occurrence of anxiety disorders and absence of substance-use disorder were significant independent predictors for higher education in male subjects.

CONCLUSIONS

In a population representative sample of young subjects, the MAOA-uVNTR 'risk genotype' predicted better life outcomes as expressed in higher level of education.

The 5HTT and MAO-A polymorphisms associate with depressive mood and climacteric symptoms in postmenopausal women

OBJECTIVE

The aim of this study was to assess the influence of the 44-bp polymorphism in the 5HTTLPR (SLC 6A4) (serotonin-transporter-linked polymorphic region, solute carrier family 6 member 4) promoter region and the 30-bpVNTR (variable number of tandem repeats) polymorphism in the MAO-A (monoamine oxidase A) promoter region on the prevalence of depressive mood and the severity of climacteric symptoms in postmenopausal women.

MATERIAL AND METHODS

The study involved 630 women from northern Poland who had their last menstrual period at least one year before the study. The women did not abuse alcohol or cigarettes, had not been diagnosed as having endocrinological, cancerous or mental diseases, and had not received psychiatric treatment by the time. This survey-based study was performed using the following research instruments: the Beck Depression Inventory (BDI), to evaluate depressive symptoms, and the Blatt-Kupperman Menopausal Index, to measure the severity of climacteric symptoms.

RESULTS

The average age of the women was 57.5 ± 6.4 years. Depressive symptoms of different severity according to the BDI were diagnosed in 29.2% of the women (minor-18.6%, moderate-7.1%, severe-3.5%) and according to the Blatt-Kupperman Menopausal Index were diagnosed in 42% of the women (minor-24.1%, moderate-9.2%, severe-8.7%). Allele 'l' was significantly more common in the women without climacteric symptoms than those with minor, moderate or severe climacteric complaints (p ≤ 0.05). There was a significant correlation between the severity of climacteric and depressive symptoms (p ≤ 0.05). The women who had severe climacteric symptoms also had more severe depressive symptoms.

CONCLUSIONS

1. The 5HTTLPR gene polymorphism contributes to climacteric symptoms in postmenopausal women. 2. The Blatt-Kupperman Menopausal Index is an instrument which can not only be used for the measurement of the severity of climacteric symptoms but also the early detection of perimenopausal women at the risk of developing depressive symptoms.

The current state of play on the molecular genetics of depression

BACKGROUND

It has been well established that both genes and non-shared environment contribute substantially to the underlying aetiology of major depressive disorder (MDD). A comprehensive overview of genetic research in MDD is presented. Method Papers were retrieved from PubMed up to December 2011, using many keywords including: depression, major depressive disorder, genetics, rare variants, gene-environment, whole genome, epigenetics, and specific candidate genes and variants. These were combined in a variety of permutations.

RESULTS

Linkage studies have yielded some promising chromosomal regions in MDD. However, there is a continued lack of consistency in association studies, in both candidate gene and genome-wide association studies (GWAS). Numerous factors may account for variable results including the use of different diagnostic approaches, small samples in early studies, population stratification, epigenetic phenomena, copy number variation (CNV), rare variation, and phenotypic and allelic heterogeneity. The conflicting results are also probably, in part, a consequence of environmental factors not being considered or controlled for.

CONCLUSIONS

Each research group has to identify what issues their sample may best address. We suggest that, where possible, more emphasis should be placed on the environment in molecular behavioural genetics to identify individuals at environmental high risk in addition to genetic high risk. Sequencing should be used to identify rare and alternative variation that may act as a risk factor, and a systems biology approach including gene-gene interactions and pathway analyses would be advantageous. GWAS may require even larger samples with reliably defined (sub)phenotypes.

The MAOA gene predicts happiness in women

Psychologists, quality of life and well-being researchers have grown increasingly interested in understanding the factors that are associated with human happiness. Although twin studies estimate that genetic factors account for 35-50% of the variance in human happiness, knowledge of specific genes is limited. However, recent advances in molecular genetics can now provide a window into neurobiological markers of human happiness. This investigation examines association between happiness and monoamine oxidase A (MAOA) genotype. Data were drawn from a longitudinal study of a population-based cohort, followed for three decades. In women, low expression of MAOA (MAOA-L) was related significantly to greater happiness (0.261 SD increase with one L-allele, 0.522 SD with two L-alleles, P=0.002) after adjusting for the potential effects of age, education, household income, marital status, employment status, mental disorder, physical health, relationship quality, religiosity, abuse history, recent negative life events and self-esteem use in linear regression models. In contrast, no such association was found in men. This new finding may help explain the gender difference on happiness and provide a link between MAOA and human happiness.

A combination of dopamine genes predicts success by professional Wall Street traders

What determines success on Wall Street? This study examined if genes affecting dopamine levels of professional traders were associated with their career tenure. Sixty professional Wall Street traders were genotyped and compared to a control group who did not trade stocks. We found that distinct alleles of the dopamine receptor 4 promoter (DRD4P) and catecholamine-O-methyltransferase (COMT) that affect synaptic dopamine were predominant in traders. These alleles are associated with moderate, rather than very high or very low, levels of synaptic dopamine. The activity of these alleles correlated positively with years spent trading stocks on Wall Street. Differences in personality and trading behavior were also correlated with allelic variants. This evidence suggests there may be a genetic basis for the traits that make one a successful trader.

Effects of MAOA promoter methylation on susceptibility to paranoid schizophrenia

This study was undertaken to analyze DNA methylation profiling at the monoamine oxidase A (MAOA) locus, in order to determine whether abnormal DNA methylation is involved in the development of schizophrenia. We recruited a total of 371 patients with paranoid schizophrenia (199 males and 172 females) and 288 unrelated control subjects (123 males and 165 females) for analysis of DNA methylation. Diagnosis was made based on the Structured Clinical Interview for DSM-VI. Genomic DNA extracted from peripheral blood was chemically modified using bisulfite, and DNA methylation profiles of the MAOA promoter were determined by BSP-sequencing. DNA methylation ratios of individual CpG residues and overall methylation ratios were measured on each subject. The results showed that there was no significant difference in overall DNA methylation ratios between patients and controls either in the female group (P = 0.42) or in the male group (P = 0.24). Of 15 CpG residues that showed significant differences in DNA methylation status between the patient group and the control group in females, eight of which had an increased level and seven, a decreased level, with a combined P value of 1 (df = 160). In male subjects, however, six individual CpG residues showed an increased methylation level with a combined P value of 5.80E-35 (df = 158). In conclusion, abnormalities of DNA methylation at the MAOA promoter may be associated with schizophrenia in males.

Rostral anterior cingulate cortex activity and early symptom improvement during treatment for major depressive disorder

In treatment trials for major depressive disorder (MDD), early symptom improvement is predictive of eventual clinical response. Clinical response may also be predicted by elevated pretreatment theta (4-7Hz) current density in the rostral anterior cingulate (rACC) and medial orbitofrontal cortex (mOFC). We investigated the relationship between pretreatment EEG and early improvement in predicting clinical outcome in 72 MDD subjects across three placebo-controlled treatment trials. Subjects were randomized to receive fluoxetine, venlafaxine, or placebo. Theta current density in the rACC and mOFC was computed with Low-Resolution Brain Electromagnetic Tomography (LORETA). An analysis of covariance examining week-8 Hamilton Depression Rating Scale (HamD) percent change, showed a significant effect of week-2HamD percent change, and a significant three-way interaction of week-2HamD percent change×treatment×rACC. Medication subjects with robust early improvement showed almost no relationship between rACC theta current density and final clinical outcome. However, in subjects with little early improvement, rACC activity showed a strong relationship with clinical outcome. The model examining the mOFC showed a trend in the three-way interaction. A combination of pretreatment rACC activity and early symptom improvement may be useful for predicting treatment response.

P2RX7 gene is associated consistently with mood disorders and predicts clinical outcome in three clinical cohorts

We investigated the effect of nine candidate genes on risk for mood disorders, hypothesizing that predisposing gene variants not only elevate the risk for mood disorders but also result in clinically significant differences in the clinical course of mood disorders. We genotyped 178 DSM-IV bipolar I and II and 272 major depressive disorder patients from three independent clinical cohorts carefully diagnosed with semistructured interviews and prospectively followed up with life charts for a median of 60 (range 6-83) months. Healthy control subjects (n = 1322) were obtained from the population-based national Health 2000 Study. We analyzed 62 genotyped variants within the selected genes (BDNF, NTRK2, SLC6A4, TPH2, P2RX7, DAOA, COMT, DISC1, and MAOA) against the presence of mood disorder, and in post-hoc analyses, specifically against bipolar disorder or major depressive disorder. Estimates for time ill were based on life charts. The P2RX7 gene variants rs208294 and rs2230912 significantly elevated the risk for a familial mood disorder (OR = 1.35, P = 0.0013, permuted P = 0.06, and OR = 1.44, P = 0.0031, permuted P = 0.17, respectively). The results were consistent in all three cohorts. The same risk alleles predicted more time ill in all cohorts (OR 1.3, 95% CI 1.1-1.6, P = 0.0069 and OR 1.7, 95% CI 1.3-2.3, P = 0.0002 with rs208294 and rs2230912, respectively), so that homozygous carriers spent 12 and 24% more time ill. P2RX7 and its risk alleles predisposed to mood disorders consistently in three independent clinical cohorts. The same risk alleles resulted in clinically significant differences in outcome of patients with major depressive and bipolar disorder.

Droplets of black bile? Development of vulnerability and resilience to depression in young age

Major depressive disorder is predicted by enduring anxiety-related personality traits, in particular by neuroticism, which have genetic foundations. Neuroticism in turn is strongly related with the genetic risk for depression. Search for gene variants associated with neuroticism and depression has led to some good candidates, but the consistency of findings is very far from ideal. Adverse life events are causal to development of mood disorders, and often the vulnerability genes can be detected only when environmental impact has been objectively assessed. Yet the continuity of depression diagnosis from early childhood to adulthood is limited, while childhood depression increases odds of other affect-related disorders such as substance abuse and personality disorders. Whether specific genes have an impact seems to depend on the period of life both because of biological maturation and differences in major environmental factors, but also active engagement--or the failure to do so--of the vulnerable subjects with their environment. It is proposed that subjects with genetically determined neurotic tendencies are likely to attempt to select coping strategies that reduce events perceived as harmful and can by this means develop resilience towards affective disorders.

Personality and illness: genetic connections?

Illness is strongly influenced by genetics. Personality traits are influenced by genetics and have linkages with, at least, affective illness. Because genetics influences both personality and illness, we studied by literature review the genes that illness and personality traits share and, by office assessment, our patient population's illnesses and personality traits. This led to the following hypothesis: illness is related to more Submissive than Dominant personality trait and thus to lower norepinephrine activity. Patient affect and personality are often noted to be subdued in chronic illness, but whether from cause or effect is difficult to determine. After reviewing the literature on wellness, personality and genes, we endeavored to explore and better delineate our impressions of illness and personality relationships and to set the stage for a genetic hypothesis by using an online personality test in an ob-gyn practice to determine which traits could be used as proxies for personality trait genes. We thus confirmed our clinical impression that women with psychiatric and/or medical illness have more Submissive personality. The medical literature on gene markers shared by Submissive personality and illness in our population suggests the hypothesis that this relationship could be mediated by genetically lower neurotransmitter activity. Both norepinephrine activity and monoamine oxidase A, the enzyme controlling its catabolism, are in concert to blunt neuronal activity in such diverse states as depression, asthma, obesity, autoimmune illness, and in smokers. Conversely, norepinephrine activity is enhanced in breastfeeders and in other settings known to be related to good health. A point for possible divergence from the hypothesis is that African-Americans have enhanced norepinephrine activity yet poorer health outcomes although the effect of environmental risk factors in African-Americans is considered prominent by researchers. The possible importance of this hypothesis is that it changes emphasis slightly from one of splitting diagnoses to one of grouping them to achieve fresh insight. If we assess what is found in common in diverse illnesses of mind and body, we have yet another tool to assess causation. Although this hypothesis is offered somewhat in a boldness of spirit to take a new look at our many perplexing clinical problems, it is also offered with humility in light of the complexity with which we deal in patient care.

The heritability of postpartum depression

Postpartum depression (PPD) is a serious mood disorder that may carry life-long consequences for a woman and her family. Multiple risk factors for PPD have been identified, including psychosocial, situational, and biological stimuli, several of which are experienced by most, if not all, postpartum women. Given the commonality of these risk factors, it is unclear why fewer than 20% of postpartum women actually develop PPD. In this review, we suggest that different susceptibility to PPD among postpartum women may be explained by the presence or absence of genetic variants that confer increased risk. We review three categories of genes known to code for proteins associated with depression in the general population or proteins known to be affected by childbirth for their possible association with PPD, including genes related to central nervous system monoamine availability, proinflammatory cytokines, and brain neuropeptides. Only two studies are available in the literature to date specifically looking at polymorphisms in postpartum women as related to PPD; both are concerned with monoamine availability. These are discussed in further depth. Conclusions regarding the contribution of genetic polymorphisms to the development of PPD are mixed. Ultimately, the complexity of the disorder and the interrelationships among different genes thought to contribute to depression suggest that much more research is required to understand the heritability of PPD. The complexity of the disorder also suggests that epigenetic influences must be considered as well when discussing susceptibility.

MAOA interacts with the ALDH2 gene in anxiety-depression alcohol dependence

BACKGROUND

Alcohol dependence is usually comorbid with anxiety disorder, depressive disorder, or both; this comorbidity may increase drinking behavior. We previously hypothesized that anxiety-depressive alcohol dependence (ANX/DEP ALC) was a genetically specific subtype of alcohol dependence. ANX/DEP ALC may be related to dopamine and serotonin, which are catalyzed by monoamine oxidase A (MAOA) and acetaldehyde dehydrogenase 2 (ALDH2). The aim of this study was to determine whether the interaction between the MAOA and the ALDH2 genes is associated with ANX/DEP ALC.

METHODS

We recruited 383 Han Chinese men in Taiwan: 143 ANX/DEP ALC and 240 healthy controls. The diagnosis of ANX/DEP ALC (alcohol dependence with a past or current history of anxiety, depressive disorder, or both) was made using DSM-IV criteria. Genotypes of ALDH2 and MAOA-uVNTR (variable number of tandem repeat located upstream) were determined using PCR-RFLP.

RESULTS

The ALDH2, but not the MAOA-uVNTR, polymorphism was associated with ANX/DEP ALC. After stratifying the MAOA-uVNTR polymorphism, we found a stronger association between the ALDH2*1/*2 and *2/*2 genotypes and the controls in the MAOA-uVNTR 4-repeat subgroup. Logistic regression significantly associated the interaction between ALDH2 and MAOA variants with ANX/DEP ALC.

CONCLUSION

We conclude that the MAOA and ALDH2 genes interact in ANX/DEP ALC. Although the MAOA gene alone is not associated with ANX/DEP ALC, we hypothesize that different variants of MAOA-uVNTR polymorphisms modify the protective effects of the ALDH2*2 allele on ANX/DEP ALC in Han Chinese in Taiwan.

Negative emotionality: monoamine oxidase B gene variants modulate personality traits in healthy humans

Monoamine oxidase A and B (MAOA and MAOB) appear to be involved in the pathogenesis of Major Depression, and vulnerability of Major Depression is associated with personality traits relating to positive and negative affect. This study aimed to investigate associations between MAOA and MAOB polymorphisms and personality traits of positive and negative emotionality in healthy volunteers, to elucidate mechanisms underlying personality and the risk for depression. Healthy Caucasian volunteers (N = 150) completed the Multiphasic Personality Questionnaire (MPQ), which includes independent superfactors of Positive Emotionality and Negative Emotionality. Participants were genotyped for 8 MAOA and 12 MAOB single nucleotide polymorphisms (SNPs). Association analyses for both SNPs and haplotypes were performed using the permutation approach implemented in PLINK. Negative Emotionality was significantly associated with the two highly linked MAOB polymorphisms rs10521432 and rs6651806 (p < 0.002). Findings were extended in haplotype analyses. For MAOB the 4-SNP haplotype GACG formed from rs1799836, rs10521432, rs6651806 and rs590551 was significantly related to lower Negative Emotionality scores (p < 0.002). MAOA was not related to personality in this study. Our finding provides the first evidence that MAOB polymorphisms influence levels of negative emotionality in healthy human volunteers. If confirmed, these results could lead to a better understanding of personality traits and inter-individual susceptibility developing psychiatric disorders such as major depression.