Child dopamine active transporter 1 genotype and parenting: evidence for evocative gene-environment correlations

The domain-variant indirect association between electrophysiological response to reward and ADHD presentations is moderated by dopaminergic polymorphisms

BACKGROUND

Understanding the etiopathogenesis of attention-deficit/hyperactivity disorder (ADHD) may necessitate decomposition of the heterogeneous clinical phenotype into more homogeneous intermediate phenotypes. Reinforcement sensitivity is a promising candidate, but the exact nature of the ADHD-reward relation - including how, for whom, and to which ADHD dimensions atypicalities in reward processing are relevant - is equivocal.

METHODS

Aims were to examine, in a carefully phenotyped sample of adolescents (N = 305; Mage = 15.30 years, SD = 1.07; 39.7% girls), whether functional dopaminergic polymorphisms implicated in both reward processing and ADHD (1) are differentially associated with event-related potentials (ERPs) of reward anticipation at distinct levels of ADHD risk (nno risk = 174, nat-risk = 131, ndiagnosed = 83); and (2) moderate the indirect effect of dispositional affectivity on the association between ERPs and ADHD domains.

RESULTS

In adolescents at-risk for or with ADHD, carrying a hypodopaminergic allele was associated with enhanced ERPs of attention allocation to cue and attenuated ERPs of anticipatory attention to feedback. No associations were observed in adolescents not at-risk for or without ADHD. Controlling for age and sex, both the negative indirect effect of positive affectivity (PA) on the association between ERPs and inattention and the positive indirect effect of PA on the association between ERPs and hyperactivity/impulsivity were supported only for those with high activity dopamine transporter (DAT) alleles.

CONCLUSIONS

Reward and affective processing are promising intermediate phenotypes relevant to disentangling ADHD developmental pathways. Consistent with developmental multifinality, through the successive effects of reward anticipation and positive affectivity, functional dopaminergic variants may confer protection against inattention or risk for hyperactivity/impulsivity.

Children’s ADHD and Dysregulation Problems, DAT1 Genotype and Methylation, and their Interplay with Family Environment

Background

International literature has underlined the complex interplay between genetic and environmental variables in shaping children’s emotional-behavioral functioning.

Objective

This study aimed to explore the dynamic relationship between children’s Dopamine Transporter (DAT1) genotype and methylation, and maternal and paternal affective environment, on children’s Attention Deficit Hyperactivity Disorder (ADHD) problems and dysregulation problems.

Method

In a community sample of 76 families with school-aged children, we assessed children’s DAT1 genotype and methylation, their own ADHD problems and dysregulation profile (CBCL 6–18 DP), and maternal and paternal psychopathological risk, parenting stress, and marital adjustment. Hierarchical regressions were carried out to verify the possible moderation of children’s genotype on the relationship between children’s methylation and psychopathological risk, parental environment and children’s methylation, and parental environment and children’s psychopathological risk.

Results

The levels of methylation at M1 CpG significantly predicted ADHD problems among children with 10/10 genotype, whereas high levels of methylation at M6 CpG predicted low ADHD problems for children with 9/x genotype. High levels of methylation at M3 CpG were associated with high scores of CBCL DP. DAT1 genotype moderated the relationship between maternal and paternal variables with children’s methylation and psychopathological risk. The scores of maternal and paternal Dyadic Adjustment Scale showed indirect effects on children’s methylation and psychopathological risk in relation to those exerted by risk factors.

Conclusion

Our study has supported the emerging evidence on the complex nature of children’s emotional-behavioral functioning and the associated risk and protective factors, with important implications for the planning of preventive programs.

DAT1 and Its Psychological Correlates in Children with Avoidant/Restrictive Food Intake Disorder: A Cross-Sectional Pilot Study

International research has underlined the role played by children’s and maternal psychopathological symptoms on the onset of avoidant/restrictive food intake disorder (ARFID) in early childhood. No study has considered the possible interplay between children’s dopamine transporter (DAT1) genotype and methylation, dysregulation problems and maternal psychopathological risk. This study aimed to investigate the complex relationship between these variables, considering the possible mediation role played by children’s DAT1 methylation on the relationship between mothers’ psychopathological risk and children’s dysregulation problems, moderated by children’s DAT1 genotype. Our sample consisted of 94 early children and their mothers, divided into four subgroups, based on children’s ARFID subtypes (irritable/impulsive (I/I), sensory food aversions (SFA), post-traumatic feeding disorders subtypes (PTFD), and a non-clinical group (NC)). We addressed children’s dysregulation problems and maternal psychopathological risk, and collected children’s DNA through buccal swabs. Results showed that children’s 9/x genotype was associated with PTFD and NC groups, whereas the 10/10 genotype was associated with the SFA group, with large effect size. There were significant large differences in the study groups on children’s DAT1 total methylation, children’s dysregulation problems, and maternal psychopathological risk. Children’s DAT1 methylation did not mediate the relationship between mother’s psychopathological risk and children’s dysregulation problems, but there was a significant large direct effect. Children’s 9/x genotype moderated the relationship between maternal psychopathological risk and children’s DAT1 methylation but, respectively, with a large and small effect. Our pilot study suggested that the relationship between children’s DAT1 genotype and methylation, dysregulation problems, and maternal psychopathological risk has a crucial contribution to ARFID.

Integrating the study of personality and psychopathology in the context of gene-environment correlations across development

OBJECTIVE

A key principle of individual differences research is that biological and environmental factors jointly influence personality and psychopathology. Genes and environments interact to influence the emergence and stability of both normal and abnormal behavior (i.e., genetic predisposition, X, is exacerbated or buffered under environmental conditions, Y, or vice versa), including by shaping the neural circuits underpinning behavior. The interplay of genes and environments is also reflected in various ways in which they are correlated (i.e., rGE). That is, the same genetic factors that give rise to personality or psychopathology also shape that person's environment.

METHODS

In this review, we outline passive, evocative, and active rGE processes and review the findings of studies that have addressed rGE in relation to understanding individual differences in personality and psychopathology across development.

RESULTS

Throughout, we evaluate the question of whether it is possible, not only to differentiate the person from their problems, but also to differentiate the person from their problems and their environment.

CONCLUSIONS

We provide recommendations for future research to model rGE and better inform our ability to study personality and psychopathology, while separating the influence of the environment.

Effects of interactions between variation in dopaminergic genes, traumatic life events, and anomalous self-experiences on psychosis proneness: Results from a cross-sectional study in a nonclinical sample

Background

There is a growing number of studies showing interactions between genetic polymorphisms associated with dopaminergic neurotransmission and traumatic life events (TLEs) on a risk of psychotic-like experiences (PLEs). Anomalous self-experiences (ASEs) have been associated both with TLEs as well as with PLEs. However, it remains unknown what is the role of ASEs in the complexity of gene–environment interactions on the emergence of PLEs.

Patients and methods

We included 445 young adults—university students from three big cities in Poland. We used the Traumatic Events Checklist to assess TLEs, the Inventory of Psychotic-Like anomalous self-experiences in order to measure ASEs, and the Prodromal Questionnaire (PQ16) to record the level of PLEs. The following gene polymorphisms, related to dopaminergic neurotransmission, were determined: the catechol-O-methyltransferase (COMT) rs4680 polymorphism, the dopamine D2 receptor (DRD2) rs6277 polymorphism, and the dopamine transporter 1 (DAT1) rs28363170 polymorphism.

Results

There was a significant effect of the interaction between the DAT1 polymorphism, a severity of ASEs, and a history of TLEs on the level of PLEs. Among the DAT1 10R/10R homozygotes with low level of ASEs, a severity of PLEs was significantly higher in individuals with a history of any TLEs. Higher scores of the PQ16 were associated with a greater severity of ASEs both in the DAT1 9R allele carriers and the DAT1 10R/10R homozygotes.

Conclusion

Our findings imply that genetic liability related to aberrant dopamine transport might impact the association between TLEs and PLEs in subjects with high levels of ASEs.

Emotional-Behavioral Regulation, Temperament and Parent-Child Interactions Are Associated with Dopamine Transporter Allelic Polymorphism in Early Childhood: A Pilot Study

International research has highlighted the role played by individual genetic polymorphism, children’s emotional-behavioral functioning, and quality of parent–child feeding interaction in shaping children’s development. Few studies have focused on the dopamine transporter (DAT1) gene in these processes. In a community sample of 81 families with young children aged between 19 and 28 months (37 males and 44 females), this pilot study aimed to explore possible relationships between children’s DAT1 genotype (9/x: 9/9, 9/19 contrasted to 10/10), their own psychological profiles, parental psychopathological risk, and the quality of mother–child and father–child feeding interactions. Children’s DAT1 genotype was assessed collecting DNA through buccal; children’s temperament and emotional-behavioral regulation, and parental psychopathological risk were assessed, respectively, through report-form and self-report instruments; then, dyadic exchanges were videotaped during a mealtime, and coded based on the Scala di Valutazione dell′Interazione Alimentare (SVIA). Results showed significant differences in the variables under study based on children’s DAT1 genotype, with a higher risk associated with the 10/10. Our findings have provided preliminary new evidence on the relationship between a different child’s polymorphisms, their own emotional-behavioral functioning, and the quality of the family environment, with important implications for the planning of more targeted prevention programs.

Relationship between parents' mental disorders and socioeconomic status and offspring's psychopathology: A cross-sectional study

Mental disorders (MD) are one of the main causes of the disease burden worldwide. Associations between socioeconomic status (SES) and presence of MD in parents have been related with increased odds of MD in offspring. However, there is a lack of population-based research in this field. The aim of the present study was to examine together the relationship between the presence of MD in children, and the SES and presence of MD in their parents, in a whole of population data. A gender approach was undertaken aiming to discern how these variables influence children's mental health when related with the father and the mother. Using administrative individual data from the National Health System, a retrospective cross-sectional study was conducted. The entire children population aged 6 to 15 resident in Catalonia in 2017 was examined. A logistic regression model was performed. Low SES was associated with increased odds of children's MD. Offspring of a parent with MD were at more risk of presenting MD than offspring of parents without these problems. Although these associations were consistent for both boys and girls when looking at the father's or mother's SES and MDs, the mother's SES and MDs showed a higher association with the offspring's MDs than the father's. Lowest associations, found for boys when looking at the father's SES and MDs, were: OR of 1.21, 95%CI 1.16 to 1.27 for lowest SES, and OR of 1.66, 95%CI 1.61 to 1.70 for parental MDs. Children's familiar environment, which includes SES and mental health of parents, plays an important role in their mental health. Socially constructed gender roles interfere with SES and parent's MD. These findings support the relevance of examining MD and its risk factors within a gender approach.

Children's DAT1 Polymorphism Moderates the Relationship Between Parents' Psychological Profiles, Children's DAT Methylation, and Their Emotional/Behavioral Functioning in a Normative Sample

Parental psychopathological risk is considered as one of the most crucial features associated with epigenetic modifications in offspring, which in turn are thought to be related to their emotional/behavioral profiles. The dopamine active transporter (DAT) gene is suggested to play a significant role in affective/behavioral regulation. On the basis of the previous literature, we aimed at verifying whether children’s DAT1 polymorphisms moderated the relationship between parents’ psychological profiles, children’s emotional/behavioral functioning, and DAT1 methylation in a normative sample of 79 families with school-age children (Ntot = 237). Children’s biological samples were collected through buccal swabs, while Symptom Check-List-90 item Revised, Adult Self Report, and Child Behavior Check-List/6–18 was administered to assess parental and children’s psychological functioning. We found that higher maternal externalizing problems predicted the following: higher levels of children’s DAT1 methylation at M1, but only among children with 10/10 genotype; higher levels of methylation at M2 among children with 10/10 genotype; while lower levels for children with a 9-repeat allele. There was also a positive relationship between fathers’ externalizing problems and children’s externalizing problems, only for children with a 9-repeat allele. Our findings support emerging evidence of the complex interplay between genetic and environmental factors in shaping children’ emotional/behavioral functioning, contributing to the knowledge of risk variables for a child’s development and psychological well-being.

Gene-environment correlations in parental emotional warmth and intolerance: genome-wide analysis over two generations of the Young Finns Study

BACKGROUND

Genomic analysis of the child might offer new potential to illuminate human parenting. We examined whether offspring (G2) genome-wide genotype variation (SNPs) is associated with their mother's (G1) emotional warmth and intolerance, indicating a gene-environment correlation. If this association is stronger than between G2's genes and their emotional warmth and intolerance toward their own children, then this would indicate the presence of an evocative gene-environment correlation. To further understand how G1 mother's parenting has been evoked by genetically influenced characteristics of the child (G2), we examined whether child (G2) temperament partially accounted for the association between offspring genes and parental responses.

METHODS

Participants were from the Young Finns Study. G1 mothers (N = 2,349; mean age 39 years) self-reported the emotional warmth and intolerance toward G2 in 1980 when the participants were from 3 to 18 years old. G2 participants answered the same parenting scales in 2007/2012 (N = 1,378; mean age = 38 years in 2007; 59% female) when their children were on average 11 years old. Offspring temperament traits were self-reported in 1992 (G2 age range 15-30 years). Estimation of the phenotypic variance explained by the SNPs of G2 was done by genome-wide complex trait analysis with restricted maximum likelihood (GCTA-GREML).

RESULTS

Results showed that the SNPs of a child (G2) explained 22.6% of the phenotypic variance of maternal intolerance (G1; p-value = .039). G2 temperament trait negative emotionality explained only 2.4% points of this association. G2 genes did not explain G1 emotional warmth or G2's own emotional warmth and intolerance. However, further analyses of a combined measure of both G1 parenting scales found genetic effects. Parent or child gender did not moderate the observed associations.

CONCLUSIONS

Presented genome-wide evidence is pointing to the important role a child plays in affecting and shaping his/her family environment, though the underlying mechanisms remain unclear.

Gene-Environment Correlation Between the Dopamine Transporter Gene (DAT1) Polymorphism and Childhood Experiences of Abuse

In the present study, we investigated the possible gene-environment correlation between the dopamine transporter gene (DAT1) polymorphism and childhood experiences of abuse and neglect. Genetic information was obtained from 1,442 male and 2,178 female twins and their siblings drawn from a Finnish population-based sample. The Childhood Trauma Questionnaire was used to measure the childhood experiences of abuse and neglect. In men, the DAT1 polymorphism was associated with having experienced sexual abuse in childhood, such that men with the 9R9R genotype reported less sexual abuse experiences than men with the 9R10R or the 10R10R genotypes. In women, there was an association between the DAT1 polymorphism and childhood experiences of emotional abuse, such that women with the 9R9R genotype reported less emotional abuse experiences than women with the 9R10R or 10R10R genotypes. No other associations between the DAT1 polymorphism and childhood experiences of abuse and neglect were found. In sum, the results suggested that some genetic components might predispose children to experience childhood abuse and neglect. Possible reasons for this association were discussed.

Gene-environment correlations in the cross-generational transmission of parenting: Grandparenting moderates the effect of child 5-HTTLPR genotype on mothers' parenting

Evidence suggests that parenting is associated cross-generationally and that children's genes may elicit specific parenting styles (evocative gene-environment correlation). This study examined whether the effect of children's genotype, specifically 5-HTTLPR, on mothers' parenting behaviors was moderated by her own parenting experiences from her mother. Two independent samples of three-year-olds (N = 476 and 405) were genotyped for the serotonin transporter gene, and observational measures of parenting were collected. Mothers completed measures of the parenting they received as children. The child having a short allele on 5-HTTLPR was associated with more maternal hostility (sample 1 and 2) and with less maternal support (sample 1), but only if the mother reported lower quality grandmothers' parenting (abuse and indifference in Sample 1 and lower levels of grandmother care in Sample 2). Results support the possibility of a moderated evocative gene-environment correlation.

Catechol-O-Methyltransferase gene (val158met) polymorphisms and anxious symptoms in early childhood: The roles of hypothalamus-pituitary-adrenal axis reactivity and life stress

Individual differences in hypothalamus-pituitary-adrenal (HPA) axis reactivity to stress (measured via salivary cortisol) have been widely implicated in the etiology of internalizing problems such as depression and anxiety. Literature suggests that stress during early childhood is an important source of contextual risk although its effects may be moderated by polymorphisms of neurotransmitter genes. The COMT val158met is one such polymorphism, and literature documents its link to internalizing problems. To extend these findings, and to better understand the role of this polymorphism in developmental risk, we investigated links between the val158met polymorphism and early-age cortisol response. Additionally, we investigated whether cortisol reactivity mediated the link between COMT and emerging internalizing symptoms. The study was conducted in a community sample of 409 preschoolers. Saliva samples were collected pre-stress task (baseline) and every 10min post-stress task for one-hour to asses cortisol response. Child anxious and depressive symptoms were tabulated based on parent-reports. Markers of early childhood stress included marital discord, socio-economic status and the UCLA Life Stress Interview. Findings indicated that the val158met polymorphism is associated with childhood cortisol response (p<0.05). A gene-environment interaction between val158met and life stress also predicted child anxiety symptoms (p<0.01). Finally, cortisol response mediated the main-effect of val158met on child anxiety symptoms (pathway ps<0.05). Analyses suggest that COMT val158met moderates the influence of early life stress on preschool-age symptoms of anxiety. Additionally, cortisol reactivity acts as a mechanistic mediator of the main-effect of COMT genotype on child anxious symptoms.

DNA Methylation at the DAT Promoter and Risk for Psychopathology: Intergenerational Transmission between School-Age Youths and Their Parents in a Community Sample

BACKGROUND

The effect of gene polymorphisms and promoter methylation, associated with maladaptive developmental outcomes, vary depending on environmental factors (e.g., parental psychopathology). Most studies have focused on 0- to 5-year-old children, adolescents, or adults, whereas there is dearth of research on school-age youths and pre-adolescents.

METHODS

In a sample of 21 families recruited at schools, we addressed parents' psychopathological symptoms (through SCL-90-R); offspring emotional-behavioral functioning (through CBCL-6-18); dopamine transporter gene (DAT1) for epigenetic status of the 5'-untranslated region (UTR) and for genotype, i.e., variable number of tandem repeats polymorphism at the 3'-UTR. Possible associations were explored between bio-genetic and psychological characteristics within the same individual and between triplets of children, mothers, and fathers.

RESULTS

DAT methylation of CpG at positions M1, M6, and M7 in mothers was correlated with maternal (phobic) anxiety, whereas in fathers' position M6 was related to paternal depression, anxiety, hostility, psychoticism, and higher Global Severity Index (GSI). No significant correlations were found between maternal and offspring DAT methylation. Significant correlations were found between fathers' methylation at CpG M1 and children's methylation at CpG M6. Linear regressions showed that mothers and fathers' GSI predicted children's methylation at CpG sites M2, M3, and M6, whereas fathers' GSI predicted children's methylation at CpG sites, particularly M1, M2, and M6. Moreover, offspring methylation of DAT at CpG M2 predicted somatic complaint, internalizing and attention problems; methylation of DAT at CpG M6 predicted withdraw.

CONCLUSION

This study may have important clinical implication for the prevention and treatment of emotional-behavioral difficulties in children, as it adds to previous knowledge about the role of genetic and environmental factors in predicting psychopathological symptoms within non-clinical populations.

Behavior and inhibitory control in children with prenatal exposure to antidepressants and medically untreated depression

PURPOSE

The present study investigates child development following prenatal exposure to maternal use of selective serotonin reuptake inhibitors (SSRIs; N = 28), versus prenatal exposure to medically untreated depression (N = 42), and no exposure (N = 33).

METHODS

When the children reached 5-6 years of age, child cognitive abilities were measured using selected tests from Wechsler Preschool and Primary Scale of Intelligence-Revised (WPPSI-r), Neuropsychological Assessment II (NEPSY-II), and the Attention Network Test. Maternal reports of child behavioral problems were collected using the Child Behavior Checklist (CBCL).

CONCLUSION

Analyses of variance revealed no effects of prenatal exposure to depression or SSRIs upon general cognition or inhibition. Regarding behavioral problems, there was a significant negative association between both SSRI and depression exposure upon externalizing, and between SSRI exposure and internalizing problems. The results are interpreted in light of theories on interactive specialization and reactivity.

Parent-offspring transaction: Mechanisms and the value of within family designs

This article is part of a Special Issue "Parental Care". Parenting is best understood as a transactional process between parents and their offspring. Each responds to cues in the other, adapting their own behavior to that of their partner. One of the goals of parenting research in the past twenty years has been to untangle reciprocal processes between parents and children in order to specify what comes from the child (child effects) and what comes from the parent (parent effects). Child effects have been found to relate to genetic, pre and perinatal, family-wide, and child-specific environmental influences. Parent effects relate to stresses in the current context (e.g. financial strain, marital conflict), personality and ethnicity but also to adverse childhood experiences (e.g. parental mental health and substance abuse, poverty, divorce). Rodent models have allowed for the specification of biological mechanisms in parent and child effects, including neurobiological and genomic mechanisms, and of the causal role of environmental experience on outcomes for offspring through random assignment of offspring-mother groupings. One of the methods that have been developed in the human and animal models to differentiate between parent and child effects has been to study multiple offspring in the family. By holding the parent steady, and studying different offspring, we can examine the similarities and differences in how parents parent multiple offspring. Studies have distinguished between family average parenting, child-specific parenting and family-wide dispersion (the within family standard deviation). These different aspects of parenting have been differentially linked to offspring behavioral phenotypes.

Mesocorticolimbic dopamine functioning in primary psychopathy: A source of within-group heterogeneity

Despite similar emotional deficiencies, primary psychopathic individuals can be situated on a continuum that spans from controlled to disinhibited. The constructs on which primary psychopaths are found to diverge, such as self-control, cognitive flexibility, and executive functioning, are crucially regulated by dopamine (DA). As such, the goal of this review is to examine which specific alterations in the meso-cortico-limbic DA system and corresponding genes (e.g., TH, DAT, COMT, DRD2, DRD4) might bias development towards a more controlled or disinhibited expression of primary psychopathy. Based on empirical data, it is argued that primary psychopathy is generally related to a higher tonic and population activity of striatal DA neurons and lower levels of D2-type DA receptors in meso-cortico-limbic projections, which may boost motivational drive towards incentive-laden goals, dampen punishment sensitivity, and increase future reward-expectancy. However, increasingly higher levels of DA activity in the striatum (moderate versus pathological elevations), lower levels of DA functionality in the prefrontal cortex, and higher D1-to-D2-type receptor ratios in meso-cortico-limbic projections may lead to increasingly disinhibited and impetuous phenotypes of primary psychopathy. Finally, in order to provide a more coherent view on etiological mechanisms, we discuss interactions between DA and serotonin that are relevant for primary psychopathy.

Gene–environment correlation in developmental psychopathology

Modern research acknowledges that psychopathology and individual differences in normal development are the joint products of both biological and social influences. Although there have been numerous publications on Gene × Environment interactions in the past decade, gene–environment correlation is another important form of gene–environment interplay that has received less attention. This Special Section demonstrates, using a range of methodological approaches, the importance of gene–environment correlation in developmental psychopathology. Several types of gene–environment correlation are described, including passive, evocative, and active. Other studies highlight the potential for gene–environment correlation to obscure associations between risk exposures and child psychopathology. Future directions for gene–environment correlation research are discussed.