Associations of a regulatory polymorphism of monoamine oxidase-A gene promoter (MAOA-uVNTR) with symptoms of depression and sleep quality

Good parent-child relationship protects against alcohol use in maltreated adolescent females carrying the MAOA-uVNTR susceptibility allele

Introduction

Risk-allele carriers of a Monoamine oxidase A (MAOA) gene, short-allele (MAOA-S) in males and long-allele (MAOA-L) in females, in the presence of a negative environment, are associated with alcohol misuse. Whether MAOA-S/L alleles also present susceptibility to a positive environment to mitigate the risk of alcohol misuse is unknown. Thus, we assessed the association of the three-way interaction of MAOA, maltreatment, and positive parent-child relationship with alcohol consumption among adolescents.

Methods

This prospective study included 1416 adolescents (females: 59.88%) aged 16 - 19 years from Sweden, enrolled in the "Survey of Adolescent Life in Västmanland" in 2012. Adolescents self-reported alcohol consumption, maltreatment by a family (FM) or non-family member (NFM), parent-child relationship, and left saliva for MAOA genotyping.

Results and discussion

We observed sex-dependent results. Females carrying MAOA-L with FM or NFM and a good parent-child relationship reported lower alcohol consumption than those with an average or poor parent-child relationship. In males, the interactions were not significant. Results suggest MAOA-L in females, conventionally regarded as a "risk", is a "plasticity" allele as it is differentially susceptible to negative and positive environments. Results highlight the importance of a good parent-child relationship in mitigating the risk of alcohol misuse in maltreated individuals carrying genetic risk. However, the interactions were not significant after adjusting to several environmental and behavioural covariates, especially parent's alcohol use, negative parent-child relationship, and nicotine use (smoking and/or snus), suggesting predictor and outcome intersection. Future studies and frameworks for preventive strategies should consider these covariates together with alcohol consumption. More studies with larger sample sizes are needed to replicate the findings.

X-Chromosome Dependent Differences in the Neuronal Molecular Signatures and Their Implications in Sleep Patterns

Biological factors and mechanisms that drive sex differences observed in sleep disturbances are understudied and poorly understood. The extent to which sex chromosome constitution impacts on sex differences in circadian patterns is still a knowledge void in the sleep medicine field. Here we focus on the neurological consequences of X-chromosome functional imbalances between males and females and how this molecular inequality might affect sex divergencies on sleep. In light of the X-chromosome inactivation mechanism in females and its implications in gene regulation, we describe sleep-related neuronal circuits and brain regions impacted by sex-biased modulations of the transcriptome and the epigenome. Benefited from recent large-scale genetic studies on the interplay between X-chromosome and brain function, we list clinically relevant genes that might play a role in sex differences in neuronal pathways. Those molecular signatures are put into the context of sleep and sleep-associated neurological phenotypes, aiming to identify biological mechanisms that link X-chromosome gene regulation to sex-biased human traits. These findings are a significant step forward in understanding how X-linked genes manifest in sleep-associated transcriptional networks and point to future research opportunities to address female-specific clinical manifestations and therapeutic responses.

Social jetlag and risk of depression: Results from the Korea National Health and Nutrition Examination Survey

BACKGROUND

Social jetlag, which is the mismatch between endogenous rhythm and social timing, is prevalent among the working population. Social jetlag may result in mood changes; however, evidence of relationship between social jetlag and depressive disorders has not been fully verified. Hence, this study aimed to investigate the association between social jetlag and depressive symptoms in a representative working population of South Korea.

METHODS

This study included 5447 Korean employees in the Korea National Health and Nutrition Examination Survey. Social jetlag was calculated as the difference between the midpoint of sleep time on weekdays and free days. Depressive symptoms were assessed using Patient Health Questionnaire-9. Multiple logistic regression was used to estimate the odds ratio after adjusting for confounding factors. Moreover, social jetlag and continuous depression scores were evaluated using linear regression and generalized additive models.

RESULTS

The proportion of the participants who had >2 h of social jetlag was 10.26 %. Depressive symptoms increased as social jetlag increased. Multiple logistic regression analysis showed that the adjusted OR (95 % confidence interval) for 1 to 2 h of social jetlag was 1.355 (0.891-2.059) and for >2 h was 1.859 (1.084-3.187), which <1 h was reference.

LIMITATIONS

This study used a cross-sectional design and measurements were based on self-reported scales.

CONCLUSION

This study found that social jetlag and depressive symptoms were significantly related in the Korean working population.

Sex Differences in Depression Caused by Early Life Stress and Related Mechanisms

Depression is a common psychiatric disease caused by various factors, manifesting with continuous low spirits, with its precise mechanism being unclear. Early life stress (ELS) is receiving more attention as a possible cause of depression. Many studies focused on the mechanisms underlying how ELS leads to changes in sex hormones, neurotransmitters, hypothalamic pituitary adrenocortical (HPA) axis function, and epigenetics. The adverse effects of ELS on adulthood are mainly dependent on the time window when stress occurs, sex and the developmental stage when evaluating the impacts. Therefore, with regard to the exact sex differences of adult depression, we found that ELS could lead to sex-differentiated depression through multiple mechanisms, including 5-HT, sex hormone, HPA axis, and epigenetics.

The Genetics of Sleep Disorders in Children: A Narrative Review

Sleep is a universal, highly preserved process, essential for human and animal life, whose complete functions are yet to be unravelled. Familial recurrence is acknowledged for some sleep disorders, but definite data are lacking for many of them. Genetic studies on sleep disorders have progressed from twin and family studies to candidate gene approaches to culminate in genome-wide association studies (GWAS). Several works disclosed that sleep-wake characteristics, in addition to electroencephalographic (EEG) sleep patterns, have a certain degree of heritability. Notwithstanding, it is rare for sleep disorders to be attributed to single gene defects because of the complexity of the brain network/pathways involved. Besides, the advancing insights in epigenetic gene-environment interactions add further complexity to understanding the genetic control of sleep and its disorders. This narrative review explores the current genetic knowledge in sleep disorders in children, following the International Classification of Sleep Disorders-Third Edition (ICSD-3) categorisation.

Questions in the Chemical Enzymology of MAO

We have structure, a wealth of kinetic data, thousands of chemical ligands and clinical information for the effects of a range of drugs on monoamine oxidase activity in vivo. We have comparative information from various species and mutations on kinetics and effects of inhibition. Nevertheless, there are what seem like simple questions still to be answered. This article presents a brief summary of existing experimental evidence the background and poses questions that remain intriguing for chemists and biochemists researching the chemical enzymology of and drug design for monoamine oxidases (FAD-containing EC 4.1.3.4).

Genetic and epigenetic serotonergic markers predict the ability to recognize mental states

The serotonergic (5-HT) system is related to affective and cognitive processes and explains behavioral variability in the normal and psychopathological range. For this reason, the hypothesis was put forward that genetic and epigenetic markers related to 5-HT metabolism predict individual differences in social cognitive functioning. Social cognitions are complex mental processes necessary for perceiving, interpreting and reacting to the behaviors of others. In order to test this hypothesis one of the most prominent theory of mind tasks, the reading the mind in the eye test (RMET), was administered to N = 435 participants and measures of performance were related to the functional MAO-A VNTR polymorphism (relevant for 5-HT catabolism) and to epigenetic markers in the promoter of the TPH-2 gene (relevant for 5-HT synthesis). It was postulated that genetic and epigenetic markers of high 5-HT activity are positively related to RMET performance. Results show that the MAO-A high activity allele, together with the degree of methylation at a promoter CpG site on the TPH-2 gene explain significant proportions of variance in the RMET performance even after controlling for age and sex effects. Present findings yield evidence for the importance of 5-HT for social cognition. Based on additional findings, the role of a TRP-rich diet for theory of mind functions is discussed.

Brain mechanisms of insomnia: new perspectives on causes and consequences

While insomnia is the second most common mental disorder, progress in our understanding of underlying neurobiological mechanisms has been limited. The present review addresses the definition and prevalence of insomnia and explores its subjective and objective characteristics across the 24-hour day. Subsequently, the review extensively addresses how the vulnerability to develop insomnia is affected by genetic variants, early life stress, major life events, and brain structure and function. Further supported by the clear mental health risks conveyed by insomnia, the integrated findings suggest that the vulnerability to develop insomnia could rather be found in brain circuits regulating emotion and arousal than in circuits involved in circadian and homeostatic sleep regulation. Finally, a testable model is presented. The model proposes that in people with a vulnerability to develop insomnia, the locus coeruleus is more sensitive to-or receives more input from-the salience network and related circuits, even during rapid eye movement sleep, when it should normally be sound asleep. This vulnerability may ignite a downward spiral of insufficient overnight adaptation to distress, resulting in accumulating hyperarousal, which, in turn, impedes restful sleep and moreover increases the risk of other mental health adversity. Sensitized brain circuits are likely to be subjectively experienced as "sleeping with one eye open". The proposed model opens up the possibility for novel intervention studies and animal studies, thus accelerating the ignition of a neuroscience of insomnia, which is direly needed for better treatment.

The MAOA Gene Influences the Neural Response to Psychosocial Stress in the Human Brain

The stress response is regulated by many mechanisms. Monoamine oxidase A (MAOA) has been related to many mental illnesses. However, few studies have explored the relationship between MAOA and acute laboratory-induced psychosocial stress with functional magnetic resonance imaging (fMRI). In the current study, the Montreal Imaging Stress Task (MIST) and fMRI were used to investigate how MAOA influences the stress response. Increased cortisol concentrations were observed after the task; functional connectivity between the bilateral anterior hippocampus and other brain regions was reduced during stress. MAOA-H allele carriers showed greater deactivation of the right anterior hippocampus and greater cortisol response after stress than did MAOH-L allele carriers. Hippocampal deactivation may lead to disinhibition of the hypothalamic-pituitary-adrenal (HPA) axis and the initiation of stress hormone release under stress. Our results suggest that the MAOA gene regulates the stress response by influencing the right anterior hippocampus.

A human minisatellite hosts an alternative transcription start site for NPRL3 driving its expression in a repeat number-dependent manner

Minisatellites, also called variable number of tandem repeats (VNTRs), are a class of repetitive elements that may affect gene expression at multiple levels and have been correlated to disease. Their identification and role as expression quantitative trait loci (eQTL) have been limited by their absence in comparative genomic hybridization and single nucleotide polymorphisms arrays. By taking advantage of cap analysis of gene expression (CAGE), we describe a new example of a minisatellite hosting a transcription start site (TSS) which expression is dependent on the repeat number. It is located in the third intron of the gene nitrogen permease regulator like protein 3 (NPRL3). NPRL3 is a component of the GAP activity toward rags 1 protein complex that inhibits mammalian target of rapamycin complex 1 (mTORC1) activity and it is found mutated in familial focal cortical dysplasia and familial focal epilepsy. CAGE tags represent an alternative TSS identifying TAGNPRL3 messenger RNAs (mRNAs). TAGNPRL3 is expressed in red blood cells both at mRNA and protein levels, it interacts with its protein partner NPRL2 and its overexpression inhibits cell proliferation. This study provides an example of a minisatellite that is both a TSS and an eQTL as well as identifies a new VNTR that may modify mTORC1 activity.

Moderator Effects of Life Stress on the Association between MAOA-uVNTR, Depression, and Burnout

BACKGROUND

The serotonergic and noradrenergic systems have a strong impact on several affective disorders and are key targets for psychopharmacological therapy. With respect to pathogenesis, there is a growing body of evidence showing an influence of a promoter repeat polymorphism (MAOA-uVNTR) altering the expression rate of monoamine oxidase A. However, only a few studies investigate its influence on depression with only 2 of them considering the moderating effects of life stress. For burnout, there are no studies so far investigating the genetic basis.

OBJECTIVES

The aim of the present study was to replicate an interaction effect of MAOA-uVNTR and life stress on depression, and extend these possible findings to the burnout syndrome. Especially, the latter one might help in understanding the underlying mechanisms of burnout and its association to depression.

METHOD

A total of n = 1,541 participants (n = 1,099 healthy controls, n = 442 inpatients with affective disorders) provided genetic samples and filled in self-report questionnaires measuring depression, burnout, and the extent of experienced stressful life events (SLEs).

RESULTS

A life stress x MAOA-uVNTR interaction on depression and burnout was observed in women suggesting that carriers of the high expressing allele (MAO-H) with many SLEs had the highest scores in both burnout and depression. In men, there was only a weak effect of MAOA-uVNTR on depression.

CONCLUSIONS

The results suggest a more pronounced reactivity to adverse environmental factors in carriers of the MAO-H allele. Especially the effect of life stress and MAOA-uVNTR on burnout should be independently replicated in the future as this is the first study showing this association.

Catecholamine and Indolamine Pathway: A Case-Control Study in Fibromyalgia

OBJECTIVES

Fibromyalgia (FM) is a complex syndrome characterized by widespread pain. Its etiology is unclear, and diagnosis is difficult. The aim of this study was to assess plasma levels of monoamine neurotransmitters (catecholamines, indolamines, and intermediate metabolites) in patients with FM and healthy controls to investigate possible alterations in the metabolism of these molecules in FM. We also examined potential relationships between monoamine neurotransmitters and clinical features of FM. The predictive value of these molecules in FM was determined by receiver operating characteristic analysis.

METHOD

We measured plasma catecholamines (epinephrine, norepinephrine, and dopamine), as well as indolamines and intermediary metabolites (serotonin or 5-hydroxytryptamine [5-HT], 5-hydroxyindolacetic acid [5-HIAA], 5-hydroxytryptophan [5-HTP], and N-acetyl-5-hydroxytryptamine [Nac-5-HT]) in 35 women with FM and 12 age-matched healthy women.

RESULTS

Higher levels of norepinephrine and lower levels of dopamine, 5-HT, 5-HIAA, and 5-HTP were found in women with FM in comparison with controls. Epinephrine and Nac-5-HT levels did not differ significantly between groups. Higher norepinephrine levels were associated with worse physical health status in FM patients. Also, plasma norepinephrine levels > 694.69 pg/ml might be an accurate predictor of FM.

CONCLUSIONS

These findings show evidence of the dysregulation of the catecholamine and indolamine pathway in patients with FM, which may contribute to the physiopathology of this syndrome. In addition, the determination of plasma norepinephrine levels could help in the FM diagnosis.

The Relationship Between Personality and Somatic and Psychological Distress: A Comparison of Chinese and Australian Adolescents

The extent to which correlations between personality domains and physical and psychological health generalize cross-culturally is unclear. We compared the strength of associations between the personality domains and somatic and psychological distress in Chinese (N = 2069) and a genetically informative sample of Australian (N = 2936) adolescents. We also examined the genetic and environmental etiology between personality, somatic and psychological distress in an Australian sample of 390 monozygotic twins and 698 dizygotic twins. In both populations, personality was assessed using the Junior Eysenck Personality Questionnaire. Somatic and psychological distress was assessed using the Somatic and Psychological Health Report. We found significant cultural differences in the relationship between adolescents' personality traits and somatic and psychological distress. Extraversion was positively associated with somatic distress in the Chinese but not in Australian adolescents. In the Australian twins, genetic covariation between neuroticism and somatic and psychological distress was stronger compared to the genetic associations between either psychoticism or extraversion with psychological distress.

Analysis of Sociodemographic, Psychological, and Genetic Factors Contributing to Depressive symptoms in Pre-, Peri- and Postmenopausal Women

Depressive symptoms that are faced by women in the pre-, peri-, and postmenopausal periods are determined by a wide array of sociodemographic, psychological, and biological variables. The aim of our study was to identify factors that contribute to depressive problems at this stage of life. The study included 815 healthy Polish women aged 45–60 years. The survey part was conducted using the Beck Depression Inventory (BDI), the State–Trait Anxiety Inventory (STAI), the Neuroticism–Extroversion–Openness Five Factor Inventory (NEO-FFI), and a self-developed questionnaire. Genetic analysis was also performed. Depressive symptoms were observed in 25.5% of participants. 70% of the women were postmenopausal. No statistically significant differences in the severity of depressive symptoms were demonstrated with regard to genetic variables (p > 0.05). Reproductive capacity (p < 0.001), employment (p < 0.001), and being married (p < 0.018) were found to reduce the incidence of depressive symptoms. The contribution of personality and anxiety as a trait to depressive symptoms varied. Conclusions: The factors predisposing pre-, peri-, and postmenopausal women to depressive symptoms include lower education, lack of a life partner, unemployment, high anxiety, and neurotic personality. No evidence was found for the contribution of genetic factors to depressive symptoms in the examined women.

Post-Traumatic Sleep-Wake Disorders

All living organisms that face a traumatic life event are susceptible to sleep-wake disturbances. Stress, which can result in trauma, evokes a high level of physiological arousal associated with sympathetic nervous system activation, during both sleep and wakefulness. Heredity, sex hormones, early losses, developmental factors and intra- and interpersonal conflicts, contribute to the level of baseline physiological arousal, producing either subclinical, clinical or complex clinical traits, acutely and at any time after exposure to a traumatic event. The risk of acute sleep-wake disturbances becoming disorders and syndromes depends on the type of traumatic event and all of the aforementioned factors. Taken together, with consideration for behavioural and environmental heterogeneity, in research, will aid identification and understanding of susceptibility factors in long-term sleep and wakefulness pathology after exposure to traumatic events.

Type A monoamine oxidase and serotonin are coordinately involved in depressive disorders: from neurotransmitter imbalance to impaired neurogenesis

Type A monoamine oxidase (MAOA) catabolizes monoamine transmitters, serotonin, norepinephrine and dopamine, and plays a major role in the onset, progression and therapy of neuropsychiatric disorders. In depressive disorders, increase in MAOA expression and decrease in brain levels of serotonin and norepinephrine are proposed as the major pathogenic factors. The functional polymorphism of MAOA gene and genes in serotonin signal pathway are associated with depression. This review presents recent advance in studies on the role of MAOA in major depressive disorder and related emotional disorders. MAOA and serotonin regulate the prenatal development and postnatal maintenance of brain architecture and neurocircuit, as shown by MAOA-deficient humans and MAO knockout animal models. Impaired neurogenesis in the mature hippocampus has been proposed as "adult neurogenesis" hypothesis of depression. MAOA modulates the sensitivity to stress in the stages of brain development and maturation, and the interaction of gene-environmental factors in the early stage regulates the onset of depressive behaviors in adulthood. Vice versa environmental factors affect MAOA expression by epigenetic regulation. MAO inhibitors not only restore compromised neurotransmitters, but also protect neurons from cell death in depression through induction of anti-apoptotic Bcl-2 and prosurvival neurotrophic factors, especially brain-derived neurotrophic factor, the deficiency of which is detected in depression. This review discusses novel role of MAOA and serotonin in the pathogenesis and therapy of depressive disorders.

Genetic Pathways to Insomnia

This review summarizes current research on the genetics of insomnia, as genetic contributions are thought to be important for insomnia etiology. We begin by providing an overview of genetic methods (both quantitative and measured gene), followed by a discussion of the insomnia genetics literature with regard to each of the following common methodologies: twin and family studies, candidate gene studies, and genome-wide association studies (GWAS). Next, we summarize the most recent gene identification efforts (primarily GWAS results) and propose several potential mechanisms through which identified genes may contribute to the disorder. Finally, we discuss new genetic approaches and how these may prove useful for insomnia, proposing an agenda for future insomnia genetics research.

Epigenetics and the glucocorticoid receptor: A review of the implications in depression

Depression is a serious psychiatric disorder that effects at least 350 million people worldwide today. Dysregulation of the hypothalamic-pituitary-adrenal axis (HPAA) is a robust finding in the pathophysiology of depression. This dysregulation is hypothesized to result from altered central glucocorticoid receptor (GR) levels and/or function as a consequence of chronic glucocorticoid (GC) release, leading to receptor resistance. Pivotal animal and human research to date has identified that early life exposure to prolonged levels of GCs, stress and/or depression, can induce epigenetic modifications at key regions on the GR gene that lead to alterations in GR expression and function. Epigenetics provides an attractive mechanism to explain how ones' genes and environment can interact to produce different disease phenotypes. This review aims to compile the information that has been collected to date and to identify key areas for further investigation.

Epigenetic Modifications of Major Depressive Disorder

Major depressive disorder (MDD) is a chronic disease whose neurological basis and pathophysiology remain poorly understood. Initially, it was proposed that genetic variations were responsible for the development of this disease. Nevertheless, several studies within the last decade have provided evidence suggesting that environmental factors play an important role in MDD pathophysiology. Alterations in epigenetics mechanism, such as DNA methylation, histone modification and microRNA expression could favor MDD advance in response to stressful experiences and environmental factors. The aim of this review is to describe genetic alterations, and particularly altered epigenetic mechanisms, that could be determinants for MDD progress, and how these alterations may arise as useful screening, diagnosis and treatment monitoring biomarkers of depressive disorders.

Genetic Susceptibility and Sleep Disturbance in Black Mothers of Preterm Infants: An Exploratory Study

Serotonin (5HT) is involved in emotion and sleep regulation and the 5HT transporter (5HTT) regulates 5HT function. A common 44-base pair deletion (short allele) or insertion (long allele) polymorphism in the promoter region of 5HTT (5-HTTLPR) is differentially associated with 5HTT transcription efficiency. Under stressful conditions, the short allele of 5-HTTLPR has been associated with depression and sleep disturbance. Black women are at higher risk for preterm labor and depressive symptoms. Thus, this exploratory study aimed to examine whether depressive symptoms and sleep disturbance in Black mothers would vary as a function of the 5-HTTLPR genotype when they faced the stress of infant hospitalization after preterm birth at early postpartum. A total of 30 Black mothers filled out a battery of questionnaires, including the Perceived Stress Scale, Edinburgh Postnatal Depression Scale, and General Sleep Disturbance Scale. A wrist actigraph was used to assess total sleep time and circadian activity rhythms. Buccal cells from saliva were collected to test the 5-HTTLPR genotype. Results showed that about 38% of the mothers were heterozygous for the short (S/L) allele, and 62% were homozygous for the long (L/L) allele. Mothers’ perceived global stress, depressive symptoms, and circadian activity rhythms did not vary with their 5-HTTLPR genotypes. Unexpectedly, mothers with the L/L allele reported greater sleep disturbances than those with the S/L allele. Ethnic specificity in genetic susceptibility to stress was discussed.

Genetic adaptation of the human circadian clock to day-length latitudinal variations and relevance for affective disorders

Background

The temporal coordination of biological processes into daily cycles is a common feature of most living organisms. In humans, disruption of circadian rhythms is commonly observed in psychiatric diseases, including schizophrenia, bipolar disorder, depression and autism. Light therapy is the most effective treatment for seasonal affective disorder and circadian-related treatments sustain antidepressant response in bipolar disorder patients. Day/night cycles represent a major circadian synchronizing signal and vary widely with latitude.

Results

We apply a geographically explicit model to show that out-of-Africa migration, which led humans to occupy a wide latitudinal area, affected the evolutionary history of circadian regulatory genes. The SNPs we identify using this model display consistent signals of natural selection using tests based on population genetic differentiation and haplotype homozygosity. Signals of natural selection driven by annual photoperiod variation are detected for schizophrenia, bipolar disorder, and restless leg syndrome risk variants, in line with the circadian component of these conditions.

Conclusions

Our results suggest that human populations adapted to life at different latitudes by tuning their circadian clock systems. This process also involves risk variants for neuropsychiatric conditions, suggesting possible genetic modulators for chronotherapies and candidates for interaction analysis with photoperiod-related environmental variables, such as season of birth, country of residence, shift-work or lifestyle habits.

Electronic supplementary material

The online version of this article (doi:10.1186/s13059-014-0499-7) contains supplementary material, which is available to authorized users.

African Genetic Ancestry is Associated with Sleep Depth in Older African Americans

STUDY OBJECTIVES

The mechanisms that underlie differences in sleep characteristics between European Americans (EA) and African Americans (AA) are not fully known. Although social and psychological processes that differ by race are possible mediators, the substantial heritability of sleep characteristics also suggests genetic underpinnings of race differences. We hypothesized that racial differences in sleep phenotypes would show an association with objectively measured individual genetic ancestry in AAs.

DESIGN

Cross sectional.

SETTING

Community-based study.

PARTICIPANTS

Seventy AA adults (mean age 59.5 ± 6.7 y; 62% female) and 101 EAs (mean age 60.5 ± 7 y, 39% female).

MEASUREMENTS AND RESULTS

Multivariate tests were used to compare the Pittsburgh Sleep Quality Index (PSQI) and in-home polysomnographic measures of sleep duration, sleep efficiency, apnea-hypopnea index (AHI), and indices of sleep depth including percent visually scored slow wave sleep (SWS) and delta EEG power of EAs and AAs. Sleep duration, efficiency, and sleep depth differed significantly by race. Individual % African ancestry (%AF) was measured in AA subjects using a panel of 1698 ancestry informative genetic markers and ranged from 10% to 88% (mean 67%). Hierarchical linear regression showed that higher %AF was associated with lower percent SWS in AAs (β (standard error) = -4.6 (1.5); P = 0.002), and explained 11% of the variation in SWS after covariate adjustment. A similar association was observed for delta power. No association was observed for sleep duration and efficiency.

CONCLUSION

African genetic ancestry is associated with indices of sleep depth in African Americans. Such an association suggests that part of the racial differences in slow-wave sleep may have genetic underpinnings.

The Joint Effects of Body Mass Index and MAOA Gene Polymorphism on Depressive Symptoms

The objective of the present study was to examine the joint effects of the body mass index and the MAOA gene polymorphism on depressive symptoms. In two independent Chinese samples, we measured adolescents' depressive symptoms and body mass index and collected their DNA. The results indicated that the main effects of the MAOA gene polymorphism on depressive symptoms were significant. However, the main effects of body mass index and the interaction of the MAOA gene polymorphism and body mass index on depressive symptoms were not significant. By using Chinese adolescents, this study confirmed that the MAOA gene polymorphism directly influenced adolescents' depressive symptoms.

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.

Monoamine oxidase a gene polymorphisms and bipolar disorder in Iranian population

BACKGROUND

Bipolar disorder (BPD) is a common and severe mood disorder. Although genetic factors have important rolesin the etiology of bipolar disorder, no specific gene has been identified in relation to this disorder. Monoamine oxidase gene is suggested to be associated with bipolar disorder in many studies.

OBJECTIVES

This study aimed to investigatethe role of MAOA gene polymorphisms in the etiology of bipolar disorder in Iranian population.

PATIENTS AND METHODS

This study is a case-control study, with convenient sampling. Three common polymorphisms, a CA microsatellite, a VNTR, and a RFLP were typed in 156 bipolar patients and 173 healthy controls. Patients were chosen from Imam Hossein General Hospital, Psychiatry Ward (Tehran/Iran). Controlsamples for this study consisted of 173 healthy individuals recruitedby convenient sampling. Allelic distributions of these polymorphisms were analyzed in bipolar and control groups to investigate any association with MAOA gene.

RESULTS

Significant associations were observed regarding MAOA-CA (P = 0.016) and MAOA-VNTR (P = 0.004) polymorphisms in the bipolar females. There was no association between MAOA-RFLP and bipolar disorder.

CONCLUSIONS

The obtained results confirm some previous studies regardinga gender specific association of MAOA gene with the bipolar disorder.

The heritability of insomnia progression during childhood/adolescence: results from a longitudinal twin study

STUDY OBJECTIVES

To determine prevalence and heritability of insomnia during middle/late childhood and adolescence; examine longitudinal associations in insomnia over time; and assess the extent to which genetic and environmental factors on insomnia remain stable, or whether new factors come into play, across this developmental period.

DESIGN

Longitudinal twin study.

SETTING

Academic medical center.

PATIENTS OR PARTICIPANTS

There were 739 complete monozygotic twin pairs (52%) and 672 complete dizygotic twin pairs (48%) initially enrolled and were followed up at three additional time points (waves). Mode ages at each wave were 8, 10, 14, and 15 y (ages ranged from 8-18 y).

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Clinical ratings of insomnia symptoms were assessed using the Child and Adolescent Psychiatric Assessment (CAPA) by trained clinicians, and rated according to Diagnostic and Statistical Manual of Mental Disorders (DSM)-III-R criteria for presence of 'clinically significant insomnia', over four sequential waves. Insomnia symptoms were prevalent but significantly decreased across the four waves (ranging from 16.6% to 31.2%). 'Clinically significant insomnia' was moderately heritable at all waves (h² range = 14% to 38%), and the remaining source of variance was the nonshared environment. Multivariate models indicated that genetic influences at wave 1 contributed to insomnia at all subsequent waves, and that new genetic influences came into play at wave 2, which further contributed to stability of symptoms. Nonshared environmental influences were time-specific.

CONCLUSION

Insomnia is prevalent in childhood and adolescence, and is moderately heritable. The progression of insomnia across this developmental time period is influenced by stable as well as new genetic factors that come into play at wave 2 (modal age 10 y). Molecular genetic studies should now identify genes related to insomnia progression during childhood and adolescence.

Genetic Addiction Risk Score (GARS): molecular neurogenetic evidence for predisposition to Reward Deficiency Syndrome (RDS)

We have published extensively on the neurogenetics of brain reward systems with reference to the genes related to dopaminergic function in particular. In 1996, we coined “Reward Deficiency Syndrome” (RDS), to portray behaviors found to have gene-based association with hypodopaminergic function. RDS as a useful concept has been embraced in many subsequent studies, to increase our understanding of Substance Use Disorder (SUD), addictions, and other obsessive, compulsive, and impulsive behaviors. Interestingly, albeit others, in one published study, we were able to describe lifetime RDS behaviors in a recovering addict (17 years sober) blindly by assessing resultant Genetic Addiction Risk Score (GARS™) data only. We hypothesize that genetic testing at an early age may be an effective preventive strategy to reduce or eliminate pathological substance and behavioral seeking activity. Here, we consider a select number of genes, their polymorphisms, and associated risks for RDS whereby, utilizing GWAS, there is evidence for convergence to reward candidate genes. The evidence presented serves as a plausible brain-print providing relevant genetic information that will reinforce targeted therapies, to improve recovery and prevent relapse on an individualized basis. The primary driver of RDS is a hypodopaminergic trait (genes) as well as epigenetic states (methylation and deacetylation on chromatin structure). We now have entered a new era in addiction medicine that embraces the neuroscience of addiction and RDS as a pathological condition in brain reward circuitry that calls for appropriate evidence-based therapy and early genetic diagnosis and that requires further intensive investigation.

Dopaminergic Neurogenetics of Sleep Disorders in Reward Deficiency Syndrome (RDS)

It is well-known that sleep has a vital function especially as it relates to prevention of substance-related disorders as discussed in the DSM-V. We are cognizant that certain dopaminergic gene polymorphisms have been associated with various sleep disorders. The importance of "normal dopamine homeostasis" is tantamount for quality of life especially for the recovering addict. Since it is now know that sleep per se has been linked with metabolic clearance of neurotoxins in the brain, it is parsonomiuos to encourage continued research in sleep science, which should ultimately result in attenuation of sleep deprivation especially associated with substance related disorders.

Genetic and epigenetic associations of MAOA and NR3C1 with depression and childhood adversities

Monoamine oxidase A (MAOA) harbours a polymorphic upstream variable-number tandem repeat (u-VNTR). The MAOA-L allele of the u-VNTR leads to decreased gene expression levels in vitro and has been found to increase the risk of conduct disorder in males with childhood adversities. Early-life adversities have been associated with hypermethylation of the glucocorticoid receptor (NR3C1). In this study, we first performed a genetic association analysis of the MAOA u-VNTR using individuals with depression (n = 392) and controls (n = 1276). Next, DNA methylation analyses of MAOA and NR3C1 were performed using saliva samples of depressed and control subgroups. Adult MAOA-L females with childhood adversities were found to have a higher risk of developing depression (p = 0.006) and overall MAOA methylation levels were decreased in depressed females compared to controls (mean depressed, 42% vs. mean controls, 44%; p = 0.04). One specific childhood adversity [early parental death (EPD)] was associated with hypermethylation of NR3C1 close to an NGFI-A binding site (mean EPD, 19% vs. mean non-EPD, 14%; p = 0.005). Regression analysis indicated that this association may be mediated by the MAOA-L allele (adjusted R² = 0.24, ANOVA: F = 23.48, p < 0.001). Conclusively: (1) depression in females may result from a gene × childhood-adversity interaction and/or a dysregulated epigenetic programming of MAOA; (2) childhood-adversity subtypes may differentially impact DNA methylation at NR3C1; (3) baseline MAOA-genotypic variations may affect the extent of NR3C1 methylation.

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.

Monoamine oxidase A gene polymorphism and the pathogenesis of sudden infant death syndrome

OBJECTIVES

To test the hypothesis that there is a significant association between functionally relevant allelic variants of the monoamine oxidase A (MAO-A) polymorphism and sudden infant death syndrome (SIDS).

STUDY DESIGN

In a case-control study of 142 cases of SIDS and 280 sex-matched control cases, the distribution of allelic and genotype variants of a promoter polymorphism of the MAO-A gene was examined using polymerase chain reaction locus amplification and fluorescence based fragment length analysis.

RESULTS

There was a significantly differential distribution of allelic and genotype variants between females with SIDS and controls. Moreover, there was a significant association between SIDS in females and allelic and genotype variants, each related to a higher transcriptional activity at the MAO-A locus.

CONCLUSIONS

Our results suggest a role of MAO-A in female SIDS pathogenesis exerted by functionally relevant allelic and genotype variants of the MAO-A polymorphism. However, with the complex and inconsistent evidence available to date, the impact of the MAO-A promoter polymorphism on SIDS etiology remains unclear.

Monoamine oxidase A genotype, childhood trauma, and subclinical atherosclerosis: a twin study

OBJECTIVE

A functional promoter polymorphism in the monoamine oxidase A (MAOA) gene has been implicated in neuropsychiatric disorders and also moderates the association between early-life stress and mental disorders, which often co-occur with cardiovascular disease. No study has examined the relationship between MAOA genotype, childhood trauma, and subclinical atherosclerosis. The objective of this investigation was to examine whether childhood trauma moderates the association between MAOA genotype and subclinical atherosclerosis.

METHODS

A sample including 289 middle-aged male twin pairs was studied. Subclinical atherosclerosis was assessed by brachial flow-mediated dilation (FMD) using ultrasound. Childhood trauma, before age 18 years, was measured with the Early Trauma Inventory and included physical, emotional, and sexual abuse as well as general trauma. Generalized estimating equation models were used to test the main and interactive effects of the MAOA genotype and each domain of childhood trauma on FMD, adjusting for known risk factors.

RESULTS

General trauma was the most prevalent childhood trauma (28.4%), followed by physical abuse (25.0%), emotional abuse (19.4%), and sexual abuse (11.6%). MAOA genotype was not associated with any domain of childhood trauma. There was no significant evidence for a main effect for the MAOA genotype (β = .02, p = .82) or childhood trauma (.005 < β < .10, p > .54) FMD. However, a significant interaction was observed between MAOA genotype and physical (β interaction = .37, p = .026) or emotional abuse (β interaction = .43, p = .025) on subclinical atherosclerosis.

CONCLUSIONS

Childhood trauma modulates the impact of MAOA variant on subclinical atherosclerosis, independent of traditional cardiovascular risk factors.

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 c.1460C>T polymorphism of MAO-A is associated with the risk of depression in postmenopausal women

OBJECTIVE

The aim of the study was an evaluation of possible relationships between polymorphisms of serotoninergic system genes and the risk of depression in postmenopausal women.

METHODS

We studied 332 women admitted to our department because of climacteric symptoms. The study group included 113 women with a diagnosis of depressive disorder according to the Hamilton rating scale for depression; the controls consisted of 219 women without depression. Serum 17β-estradiol concentrations were evaluated using radioimmunoassay, while polymorphisms in serotoninergic system genes: serotonin receptors 2A (HTR2A), 1B (HTR1B), and 2C (HTR2C); tryptophan hydroxylase 1 (TPH1) and 2 (TPH2), and monoamine oxidase A (MAO-A) were evaluated using polymerase chain reaction-restriction.

RESULTS

We found that the 1460T allele of MAO-A c.1460C>T (SNP 1137070) appeared with a significantly higher frequency in depressed female patients than in the control group (P = 0.011) and the combined c.1460CT + TT genotypes were associated with a higher risk of depression (P = 0.0198). Patients with the 1460TT genotype had a significantly higher 17β-estradiol concentration than patients with the 1460CT genotype (P = 0.0065) and 1460CC genotype (P = 0.0018).

CONCLUSIONS

We concluded that depression in postmenopausal women is closely related to the genetic contribution of MAO-A.

Sleep, emotional and behavioral difficulties in children and adolescents

Links between sleep and psychopathology are complex and likely bidirectional. Sleep problems and alteration of normal sleep patterns have been identified in major forms of child psychopathology including anxiety, depression and attention disorders as well as symptoms of difficulties in the full range. This review summarizes some key findings with regard to the links between sleep and associated difficulties in childhood and adolescence. It then proposes a selection of possible mechanisms underlying some of these associations. Suggestions for future research include the need to 1) use multi-methods to assess sleep; 2) measure sleep in large-scale studies; 3) conduct controlled experiments to further establish the effects of sleep variations on emotional and behavioral difficulties; 4) take an interdisciplinary approach to further understand the links between sleep and associated difficulties.

Associations between diurnal preference, sleep quality and externalizing behaviours: a behavioural genetic analysis

BACKGROUND

Certain aspects of sleep co-occur with externalizing behaviours in youth, yet little is known about these associations in adults. The present study: (1) examines the associations between diurnal preference (morningness versus eveningness), sleep quality and externalizing behaviours; (2) explores the extent to which genetic and environmental influences are shared between or are unique to these phenotypes; (3) examines the extent to which genetic and environmental influences account for these associations. method: Questionnaires assessing diurnal preference, sleep quality and externalizing behaviours were completed by 1556 young adult twins and siblings.

RESULTS

A preference for eveningness and poor sleep quality were associated with greater externalizing symptoms [r=0.28 (95% CI 0.23-0.33) and 0.34 (95% CI 0.28-0.39), respectively]. A total of 18% of the genetic influences on externalizing behaviours were shared with diurnal preference and sleep quality and an additional 14% were shared with sleep quality alone. Non-shared environmental influences common to the phenotypes were small (2%). The association between diurnal preference and externalizing behaviours was mostly explained by genetic influences [additive genetic influence (A)=80% (95% CI 0.56-1.01)], as was the association between sleep quality and externalizing behaviours [A=81% (95% CI 0.62-0.99)]. Non-shared environmental (E) influences accounted for the remaining variance for both associations [E=20% (95% CI -0.01 to 0.44) and 19% (95% CI 0.01-0.38), respectively].

CONCLUSIONS

A preference for eveningness and poor sleep quality are moderately associated with externalizing behaviours in young adults. There is a moderate amount of shared genetic influences between the phenotypes and genetic influences account for a large proportion of the association between sleep and externalizing behaviours. Further research could focus on identifying specific genetic polymorphisms common to both sleep and externalizing behaviours.

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.

Insomnia and suicidal behaviour in prisoners

Insomnia has been associated with suicidality. Prisoners have an increased risk of both insomnia and suicidal behaviour. Therefore, it was decided to examine for a relationship between insomnia and suicidal behaviour in a large group of 1420 prisoners. Prisoners had a semi-structured psychiatric interview, which included the Hamilton Depression Rating Scale (HDRS), and completed the Childhood Trauma Questionnaire, Eysenck Personality Questionnaire, Spielberg Anger Expression Inventory and Connor-Davidson Resilience Scale. It was found that 568 (61.2%) of the prisoners scored in the insomnia cluster of the HDRS and that 183 (12.8%) had attempted suicide. Regression analyses showed that insomnia was significantly and independently associated with a lifetime history of attempting suicide. Insomnia was also significantly related to actual suicidality. After controlling for confounders, axis 1 psychiatric disorder, childhood trauma, neuroticism, low resilience, and anger were significantly associated with insomnia in male prisoners. These data suggest the possibility of a relationship between insomnia and suicidality in prisoners. Assessing insomnia may be helpful when evaluating the risk of suicidality in prisoners.

Associations between APOE variants and metabolic traits and the impact of psychological stress

Objective

In a previous study, we observed that associations between APOE rs439401 and metabolic traits were moderated by chronic stress. Thus, in a population of stressed and non-stressed Danish men, we examined whether associations between APOE rs439401 and a panel of metabolic quantitative traits, all metabolic traits which may lead to T2D and CVD were moderated by psychological stress.

Methods

Obese young men (n = 475, BMI≥31.0 kg/m²) and a randomly selected control group (n = 709) identified from a population of 141,800 men were re-examined in two surveys (S-46: mean age 46, S-49: mean age 49 years) where anthropometric and biochemical measures were available. Psychological stress factors were assessed by a self-administered 7-item questionnaire. Each item had the possible response categories “yes” and “no” and assessed familial problems and conflicts. Summing positive responses constituted a stress item score, which was then dichotomized into stressed and non-stressed. Logistic regression analysis, applying a recessive genetic model, was used to assess odds ratios (OR) of the associations between APOE rs439401 genotypes and adverse levels of metabolic traits.

Results

The APOE rs439401 TT-genotype associated positively with BMI (OR = 1.09 [1.01; 1.17]), waist circumference (OR = 1.09 [1.02; 1.17]) in stressed men at S-46. Positive associations were observed for fasting plasma glucose (OR = 1.42 [1.07; 1.87]), serum triglycerides (OR = 1.41 [1.05; 1.91]) and with fasting plasma insulin (OR = 1.48 [1.05; 2.08]) in stressed men at S-49. Rs439401 TT-genotype also associated positively with surrogate measures of insulin resistance (HOMA-IR; OR = 1.21 [1.03; 1.41]) and inversely with insulin sensitivity (Stumvoll index; OR = 0.90 [0.82; 0.99], BIGTT-S_I; OR = 0.60 [0.43; 0.85]) in stressed men. No significant associations were observed in non-stressed men, albeit the estimates showed similar but weaker trends as in stressed men.

Conclusion

The present results suggest that the APOE rs439401 TT-genotype is associated with an adverse metabolic profile in a population of psychologically stressed Danish men.

Impact of psychological stress on the associations between apolipoprotein E variants and metabolic traits: findings in an American sample of caregivers and controls

OBJECTIVE

To examine the association between apolipoprotein E (APOE) gene variants and waist circumference, fasting plasma glucose, serum insulin, serum high-density lipoprotein cholesterol, and serum triglycerides, all metabolic traits known as cardiovascular disease (CVD) endophenotypes, in a population of stressed individuals and controls. Abdominal obesity, insulin resistance, elevated serum lipid concentration, and APOE polymorphisms have been associated with CVD risk. Current evidence supports the hypothesis that gene-environment interactions modulate serum lipid concentrations.

METHODS

The association between rs769450, rs405509, rs439401, and metabolic traits were analyzed in a U.S. sample of 126 white caregivers of a relative with Alzheimer';s disease or other major dementia and 122 white controls. The associations were analyzed, using multivariate analysis of variance adjusted for age, sex, and medications.

RESULTS

Significant multivariate interactions were found, using both additive (p = .009) and dominant (p = .047) models between rs439401 (C/T) and caregiver stress in relation to a profile of metabolic variables. Univariate analyses found the TT genotype to be associated with more adverse levels of waist circumference (interaction, p = .026), triglycerides (interaction, p = .001) and high-density lipoprotein cholesterol (interaction, p = .001) among caregivers but with a more favorable profile of these endophenotypes among controls. There were no significant associations or interactions involving the other two single nucleotide polymorphisms.

CONCLUSION

The APOE rs439401 TT genotype is associated with an adverse metabolic profile among chronically stressed individuals compared with individuals not similarly stressed in whom a more favorable profile is expressed. Confirmation of these results in further research would indicate that the TT genotype can be used to identify persons at high risk for CVD when subjected to chronic stress.