Polymorphisms of two loci at the oxytocin receptor gene in populations of Africa, Asia and South Europe

Maternal outcomes related to Genetic and epigenetic Variation in the oxytocin system: A scoping review

Purpose

In this scoping review, we synthesize the literature on oxytocin and oxytocin receptor genetic and epigenetic variation in relationship to breastfeeding, maternal caregiving behavior, and maternal mental health.

Methods

A literature search was conducted in early 2022, and updated in 2023, utilizing the PRISMA scoping review reporting method, using the following MeSH headings and key terms: oxytocin, oxytocin receptor, genetics, epigenetics, methylation, pregnancy, postnatal, breastfeeding, lactation, mother-infant relations and perinatal outcomes. The search was conducted using PubMed, EMBASE, CINAHL, Google Scholar, SCOPUS, and the Cochrane Library. Inclusion criteria included: human literature which was peer reviewed and found in primary sources, printed in the English language. In addition, the study must have reported genetic/epigenetic data in either the oxytocin or oxytocin receptor gene (maternal or infant up to 12 months after birth) in relation to a breastfeeding, maternal caregiving behavior or a maternal mental health outcome. There was no date limitation. Four authors reviewed studies for eligibility. Data was extracted using a structured data extraction form.

Results

A total of 23 studies met inclusion criteria for this review (breastfeeding n = 4, maternal caregiving behavior n = 7, and maternal mental health n = 16). Seventeen papers reported on oxytocin or oxytocin receptor genotype and nine reported epigenetic associations (namely DNA methylation). These totals are greater than 23, as studies reported on multiple outcomes. One paper assessed the interaction between genotype and methylation. While a number of genotype variations were reported, the single nucleotide polymorphism rs53576 on the oxytocin receptor gene was the most studied. Overall, variation in this polymorphism was related to postnatal depression symptoms. Among numerous epigenetic markers, site -934 was the most studied methylation site, and methylation status was associated with maternal depression and maternal caregiving behavior outcomes. Results suggest that early life experiences impact adult maternal caregiving behaviors and mental health outcomes, and vary based on genetic vulnerability. Breastfeeding outcomes were minimally studied.

Conclusion

This scoping review found that genetic and epigenetic variation at the oxytocin and oxytocin receptor genes were associated with maternal caregiving behavior and mental health, likely through complex gene and environment interactions. The findings suggest that maternal early life experiences and stress impact later caregiving behaviors and mental health in the postnatal period. The findings highlight potential pathways by which environment, experiences, and genes interact to impact maternal caregiving behavior and maternal mental health.

Oxytocin receptor single nucleotide polymorphism predicts atony-related postpartum hemorrhage

BACKGROUND

Postpartum hemorrhage remains a key contributor to overall maternal morbidity in the United States. Current clinical assessment methods used to predict postpartum hemorrhage are unable to prospectively identify about 40% of hemorrhage cases. Oxytocin is a first-line pharmaceutical for preventing and treating postpartum hemorrhage, which acts through oxytocin receptors on uterine myocytes. Existing research indicates that oxytocin function is subject to variation, influenced in part by differences in the DNA sequence within the oxytocin receptor gene. One variant, rs53576, has been shown to be associated with variable responses to exogenous oxytocin when administered during psychological research studies. How this variant may influence myometrial oxytocin response in the setting of third stage labor has not been studied. We tested for differences in the frequency of the oxytocin receptor genotype at rs53576 in relationship to the severity of blood loss among a sample of individuals who experienced vaginal birth.

METHODS

A case-control prospective design was used to enroll 119 postpartum participants who underwent vaginal birth who were at least 37 weeks of gestation. Cases were defined by either a 1000 mL or greater blood loss or instances of heavier bleeding where parturients were given additional uterotonic treatment due to uterine atony. Controls were matched to cases on primiparity and labor induction status. Genotype was measured from a maternal blood sample obtained during the 2^nd postpartum month from 95 participants. Statistical analysis included bivariate tests and generalized linear and Poisson regression modeling.

RESULTS

The distribution of the genotype across the sample of 95 participants was 40% GG (n = 38), 50.5% AG (n = 48) and 9.5% AA (n = 9). Blood loss of 1000 mL or greater occurred at a rate of 7.9% for GG, 12.5% for AG and 55.6% for AA participants (p = 0.005). Multivariable models demonstrated A-carriers (versus GG) had 275.2 mL higher blood loss (95% CI 96.9-453.4, p < 0.01) controlling for parity, intrapartum oxytocin, self-reported ancestry, active management of third stage or genital tract lacerations. Furthermore, A-carrier individuals had a 79% higher risk for needing at least one second-line treatment (RR = 1.79, 95% CI = 1.08-2.95) controlling for covariates. Interaction models revealed that A-carriers who required no oxytocin for labor stimulation experienced 371.4 mL greater blood loss (95% CI 196.6-546.2 mL).

CONCLUSIONS

We provide evidence of a risk allele in the oxytocin receptor gene that may be involved in the development of postpartum hemorrhage among participants undergoing vaginal birth, particularly among those with fewer risk factors. The findings, if reproducible, could be useful in studying pharmacogenomic strategies for predicting, preventing or treating postpartum hemorrhage.

A randomized trial shows dose-frequency and genotype may determine the therapeutic efficacy of intranasal oxytocin

BACKGROUND

The neuropeptide oxytocin is proposed as a promising therapy for social dysfunction by modulating amygdala-mediated social-emotional behavior. Although clinical trials report some benefits of chronic treatment, it is unclear whether efficacy may be influenced by dose frequency or genotype.

METHODS

In a randomized, double-blind, placebo-controlled pharmaco-functional magnetic resonance imaging trial (150 male subjects), we investigated acute and different chronic (every day or on alternate days for 5 days) intranasal oxytocin (24 international units) effects and oxytocin receptor genotype-mediated treatment sensitivity on amygdala responses to face emotions. We also investigated similar effects on resting-state functional connectivity between the amygdala and prefrontal cortex.

RESULTS

A single dose of oxytocin-reduced amygdala responses to all face emotions but for threatening (fear and anger) and happy faces, this effect was abolished after daily doses for 5 days but maintained by doses given every other day. The latter dose regime also enhanced associated anxious-arousal attenuation for fear faces. Oxytocin effects on reducing amygdala responses to face emotions only occurred in AA homozygotes of rs53576 and A carriers of rs2254298. The effects of oxytocin on resting-state functional connectivity were not influenced by either dose-frequency or receptor genotype.

CONCLUSIONS

Infrequent chronic oxytocin administration may be therapeutically most efficient and its anxiolytic neural and behavioral actions are highly genotype-dependent in males.

Gene-Environment Interactions in Face Categorization: Oxytocin Receptor Genotype x Childcare Experience Shortens Reaction Time

Human faces capture attention, provide information about group belonging, and elicit automatic prepared responses. Early experiences with other-race faces play a critical role in acquiring face expertise, but the exact mechanism through which early experience exerts its influence is still to be elucidated. Genetic factors and a multi-ethnic context are likely involved, but their specific influences have not been explored. This study investigated how oxytocin receptor gene (OXTR) genotypes and childcare experience interacted to regulate face categorization in adults. Information about single nucleotide polymorphisms of OXTR (rs53576) and experiences with own- and other-race child caregivers was collected from 89 Singaporean adults, who completed a visual categorization task with own- versus other-race faces. Participants were grouped into A/A homozygotes and G carriers and assigned a score to account for their type of child caregiver experience. A multivariate linear regression model was used to estimate the effect of genetic group, child caregiver experience, and their interaction on categorization reaction time. A significant interaction of genetic group and child caregiver experience (t = 2.48, p = 0.015), as well as main effects of both genetic group (t = −2.17, p = 0.033) and child caregiver experience (t = −4.29, p < 0.001) emerged. Post-hoc analysis revealed that the correlation between categorization reaction time and child caregiver experience was significantly different between the two genetic groups. A significant gene x environment interaction on face categorization appears to represent an indirect pathway through which genes and experiences interact to shape mature social sensitivity to faces in human adults.

The Interaction Effect of Parental Rejection and Oxytocin Receptor Gene Polymorphism on Depression: A Cross-Cultural Study in Non-Clinical Samples

Parental rejection has been consistently empirically implicated in a wide array of developmental, behavioural and psychological problems worldwide. However, the interaction effect between parental rejection in childhood and the oxytocin receptor genotype on psychological adjustment has yet to be investigated. The present study aimed to investigate gene–environment interaction effects between parental rejection (maternal and paternal) and oxytocin receptor (OXTR) gene polymorphisms (rs53576 and rs2254298) on depressive symptoms in adults in different cultural contexts. Adults from Italy and Japan (N = 133, age = 18–27 years, females = 68) were preliminarily genotyped and then completed the Parental Acceptance-Rejection Questionnaire for mothers and fathers and the Beck Depression Inventory. Hierarchical multiple regression analysis showed that paternal rejection was related to self-reported depression and that the effect of parental rejection was moderated by OXTR gene polymorphisms and nationality. Among Italians, OXTR rs2254298 A-carriers showed resilience to negative early parental care, whereas among Japanese, OXTR rs53576 non-A-carriers showed resistance to negative early paternal care. These findings align with expected relations between perceived acceptance–rejection and an individual’s psychological adjustment, as proposed by interpersonal acceptance–rejection theory, and indicate the need for future studies adopting a multicultural and multilevel approach to better understand how the effects of parental rejection extend into adulthood.

Impact of OXTR Polymorphisms on Subjective Well-Being: The Intermediary Role of Attributional Style

Polymorphisms in the oxytocin receptor (OXTR) gene are related to individual differences in negative emotions, such as depressive symptoms and anxiety. However, it remains unclear what the potential roles of OXTR polymorphisms are in subjective well-being (SWB), which is negatively correlated with depressive symptoms. We examined attributional styles as mediator between SWB and five polymorphisms of the oxytocin receptor gene (OXTR rs53576, rs2254298, rs1042778, rs2268494, and rs2268490) among 627 full-time college freshmen (M_age = 20.90, SD = 0.82 for male; M_age = 20.81, SD = 0.92 for female) using structural equation modeling. The results showed that individuals with the OXTR rs2254298 AA genotype and rs53576 AA/GA genotype reported higher scores on SWB, which suggested that individuals with this genotype experienced more happiness. Moreover, external attributional style partially mediated the association between OXTR rs2254298 polymorphism and SWB (β = 0.019, 95%CI [0.001, 0.036], p = 0.035). In conclusion, our findings demonstrated that the genetic variations of OXTR played a role in the individual differences of SWB, and external attribution style could mediate the association.

An interaction between early threat exposure and the oxytocin receptor in females: Disorder-specific versus general risk for psychopathology and social-emotional mediators

Early threat exposure is a transdiagnostic risk factor for psychopathology, and evidence suggests that genetic variation in the oxytocin receptor (OXTR) moderates this association. However, it is unclear if this gene-by-environment (G×E) interaction is tied to unique risk for disorder-specific outcomes or instead increases shared risk for general psychopathology. Moreover, little is known about how this G×E interaction increases risk. The current study utilized a prospective, longitudinal sample of females (n = 2,020) to examine: (a) whether the interaction between early threat exposure and OXTR variation (rs53576, rs2254298) confers risk for disorder-specific outcomes (depression, anxiety, borderline and antisocial personality disorders) and/or general psychopathology in early adulthood; and (b) whether social-emotional deficits (emotion dysregulation, callousness, attachment quality) during adolescence constitute mediating mechanisms. Consistent with hypotheses, the interactive effects of early threat exposure and OXTR variation (rs53576) predicted general psychopathology, with threat-exposed women carrying at least one copy of the rs53576 A-allele at greatest risk. This interaction was mediated via emotional dysregulation in adolescence, with threat-exposed A-allele carriers demonstrating greater emotion dysregulation, and greater emotion dysregulation predicting general psychopathology in early adulthood. Findings suggest that this G×E places women at risk for a broad range of psychopathology via effects on emotion dysregulation.

The influence of rs53576 polymorphism in the oxytocin receptor (OXTR) gene on empathy in healthy adults by subtype and ethnicity: a systematic review and meta-analysis

Empathy is essential for navigating complex social environments. Prior work has shown associations between rs53576, a single nucleotide polymorphism (SNP) located in the oxytocin receptor gene (OXTR), and generalized empathy. We undertook a systematic review and meta-analysis to assess the effects of rs53576 on subdomains of empathy, specifically cognitive empathy (CE) and affective empathy (AE), in healthy adults. Twenty cohorts of 8933 participants aged 18-98 were identified, including data from the Sydney Memory and Ageing Study, a cohort of older community adults. Meta-analyses found G homozygotes had greater generalized empathic abilities only in young to middle-aged adults. While meta-analyses of empathy subdomains yielded no significant overall effects, there were differential effects based on ethnicity. G homozygotes were associated with greater CE abilities in Asian cohorts (standardized mean difference; SMD: 0.09 [2.8·10^-3-0.18]), and greater AE performance in European cohorts [SMD: 0.12 (0.04-0.21)]. The current literature highlights a need for further work that distinguishes between genetic and ethnocultural effects and explores effects of advanced age on this relationship.

The OXTR polymorphisms are not associated with attachment dimensions: A three-approach study

Inspired by the roles of oxytocin in social behaviors, scientists have devoted considerable efforts to examine the association between the oxytocin receptor gene (OXTR) and human attachment, a personality of seek and receiving comfort from intimate figures. However, there are still a lot of controversies on the association. To clarify the relationship, this research integrated three studies: (1) A cross-sectional study indicated that the OXTR polymorphisms (i.e., rs53576 and rs2254298) were not significantly associated with attachment dimensions in a college student sample (N = 1193); (2) A three-wave study showed that the polymorphisms were not associated with the individual differences and changes of attachment dimensions in a freshmen sample (N = 657); and (3) Meta-analysis indicated that attachment dimensions were not associated with the polymorphisms of rs53576 (Anxiety: 14 samples, N = 5053; Avoidance: ten samples, N = 4273) and rs2254298 (Anxiety: ten samples, N = 3670; Avoidance: ten samples, N = 3698). Taken together, these findings provide strong evidence that the OXTR polymorphisms are not related to attachment dimensions.

Strategies for Sharing Limited Resources among Children and Adolescents in Three Traditional Societies of East Africa: Sociocultural and Genetic Factors

Egalitarianism, pursuit for equality, and altruism are the most important evolutionarily stable strategies in the human society. This study presents data on the results of economic games for sharing with a potential friend or unfamiliar peer in three ethnic groups of East Africa (Hadza, Iraqw, and Meru). The total sample was 583 children and adolescents; mean age, 13.5 ± 3.1 years. In addition, DNA analysis was carried out and the OXTR gene rs53576 single nucleotide polymorphism was genotyped for 162 Meru individuals. The pronounced individual variability in making decisions on sharing with a potential partner was established. Children and adolescents behaved altruistically towards friends significantly more frequently as compared with strangers. Carriers of the OXTR rs53576 GG variant displayed altruism significantly more frequently both to friends (U = 3376.500, p = 0.047; OR = 3.075, p = 0.032) and to strangers (U = 3478.000, p = 0.025; OR = 3.133, p = 0.007). Significant intergroup differences in egalitarianism, egoism, and altruism were also demonstrated. Data obtained suggest a positive group selection towards altruists.

Oxytocin receptor gene polymorphism (rs53576) and digit ratio associates with aggression: comparison in seven ethnic groups

Background

The specific role of the oxytocin receptor (OXTR) gene polymorphisms in emotional support seeking, related to social norms and culturally normative behavior, has been discussed in several studies. Evidence on the association between aggression and OXTR polymorphisms has also been reported. The goal of the current study was to analyze the effect of the OXTR rs53576 polymorphism, prenatal testosterone effect (second-to-fourth digit ratio, or 2D:4D), and culture on aggression assessed with the Buss-Perry Aggression Questionnaire (BPAQ).

Methods

The data were collected in Russia and Tanzania and included seven ethnic groups of European, Asian, and African origin. The total sample included 1705 adults (837 males, 868 females). All the subjects were evaluated with the BPAQ. As a measure of prenatal androgenization, the second and fourth digits were measured directly from hand, and the digit ratios were calculated. All the participants provided buccal samples, from which genomic DNA was extracted, and the OXTR gene rs53576 polymorphism was genotyped. Statistical analysis was performed using SPSS version 23.0; the alpha level for all analyses was set at 0.05.

Results

The ethnic group factor was the most significant predictor of ratings on BPAQ (medium effect size for physical aggression, anger and hostility scales, and low for verbal aggression). To study the effect of sex, the OXTR polymorphism, and prenatal androgenization, we conducted the z-score transformation for BPAQ scales and 2D:4D for each ethnic group and pooled these data into new z-score variables. According to the GLM analysis after leveling the effects of culture (z-transformation), all four scales of BPAQ demonstrated association with sex (main effects), with men scoring higher on physical and verbal aggression and women scoring higher on anger and hostility. Anger and hostility scales were also associated with OXTR polymorphism and 2D:4D of the right hand. The lowest levels of anger and hostility were observed in individuals with the AA genotype, especially in men.

Conclusions

Our data suggest that both oxytocin (OXTR gene polymorphism) and fetal testosterone (2D:4D) may significantly affect emotional (anger) and cognitive (hostility) aggression in humans, given the leveling the role of culture.

Interactions of OXTR rs53576 and emotional trauma on hippocampal volumes and perceived social support in adolescent girls

Oxytocin (OXT) is a neuropeptide involved in social behaviour and is sensitive to environmental influences to alter individual vulnerability or resilience to stress resulting in both negative and positive outcomes. The effects of the OXT receptor (OXTR) single nucleotide polymorphism (SNP) rs53576 on hippocampal and amygdala structure and functions in adults are differentially associated with susceptibility to adversity and social behaviours, but this evidence is lacking in healthy adolescents. Adolescence is a developmental period characterised by neurobiological and psychosocial changes resulting in higher susceptibility to mood disorders, particularly among girls. As the brain is highly plastic at this stage, to understand psychosocial and emotional development, clarity of the interactions between rs53576 and adversity on hippocampal and amygdala volumes and social behaviours is needed. In this study, we investigated the interactions between rs53576 and emotional trauma (ET) exposure on hippocampal and amygdala volumes of adolescent girls, and associations with parenting style, perceived social support and bullying behaviour. Based on an unbiased and corrected analytical approach, we found smaller left hippocampal volumes in higher (hET) compared to minimally (mET) exposed AA homozygotes, but no differences in G allele carriers nor in the amygdala. Within the mET AA group, larger volumes were associated with peer perceived social support, but in their hET counterparts, smaller volumes were associated with familial perceived social support. This evidence supports an important role for the hippocampus in social behaviours but extends current knowledge to suggest that hippocampal social behavioural features are contextually dependent on rs53576.

Examining the link between emotional childhood abuse and social relationships in midlife: The moderating role of the oxytocin receptor gene

BACKGROUND

A single nucleotide polymorphism (SNP), rs53576, of the oxytocin receptor gene (OXTR) has been associated with fundamental aspects of social processes and behaviors. Compared to A carriers, GG individuals have enhanced social competencies and tend to elicit more positive responses from social partners. However, the G allele of the OXTR rs53576 has also been associated with greater social sensitivity.

OBJECTIVE

The current study examined the unique influence of emotional childhood abuse on positive and negative aspects of different types of social relationships (e.g., family, spouse/partner, and friends) in midlife and whether genetic variations of OXTR rs53576 moderated these associations.

PARTICIPANTS AND SETTING

A total of 614 participants in midlife (aged 40-65), recruited for a large-scale study of Phoenix metropolitan residents (AS U Live Project), answered self-report questionnaires and provided blood samples for DNA genotyping.

METHODS

Hierarchical multiple regression analyses tested whether emotional childhood abuse predicted social support and strain for each relationship type and whether these potential linkages differed by OXTR genotype (GG versus AA/AG).

RESULTS

Overall, individuals with a history of emotional childhood abuse had less supportive and more strained relationships in midlife. For supportive family relationships, the effect of emotional childhood abuse was moderated by OXTR rs53576 (p < .001). Under conditions of experiencing more emotional abuse in childhood, GG individuals had more supportive family relationships in midlife compared to A carriers.

CONCLUSIONS

Overall, genetic variations of OXTR rs53576 may be an important candidate in understanding the development of social functioning within the context of emotional childhood abuse.

A biocultural approach to psychiatric illnesses

RATIONALE

As a species, humans are vulnerable to numerous mental disorders, including depression and schizophrenia. This susceptibility may be due to the evolution of our large, complex brains, or perhaps because these illnesses counterintuitively confer some adaptive advantage. Additionally, cultural and biological factors may contribute to susceptibility and variation in mental illness experience and expression. Taking a holistic perspective could strengthen our understanding of these illnesses in diverse cultural contexts.

OBJECTIVES

This paper reviews some of these potential factors and contextualizes mental disorders within a biocultural framework.

RESULTS

There is growing evidence that suggests cultural norms may influence inflammation, neurotransmitters, and neurobiology, as well as the illness experience. Specific examples include variation in schizophrenia delusions between countries, differences in links between inflammation and emotion between the United States and Japan, and differences in brain activity between Caucasian and Asian participants indicating that cultural values may moderate cognitive processes related to social cognition and interoception.

CONCLUSIONS

Research agendas that are grounded in an appreciation of biocultural diversity as it relates to psychiatric illness represent key areas for truly interdisciplinary research that can result in culturally sensitive treatments and highlight possible biological variation affecting medical treatment.

Oxytocin receptor gene (OXTR) and father support interact to predict depressive symptoms postpartum

Postpartum depression (PPD) is a debilitating mental illness affecting approximately 13% of mothers after birth. Both genetic and psychosocial factors contribute to PPD risk, but very little is known about how these factors interact. We tested whether the rs53576 polymorphism in the oxytocin receptor (OXTR) gene accounts for variation in the impact of low social support as a risk factor for depression among mothers during the perinatal period. New mothers (N = 220) provided saliva or blood DNA samples and completed surveys assessing PPD symptoms and perceived social support. In a significant interaction, social support from the baby's father predicted PPD symptoms to a greater extent among mothers with the GG compared to AG and AA genotypes. These results add to converging evidence that variation in OXTR rs53576 moderates the impact of the social environment on PPD.

Genetic and epigenetic regulatory mechanisms of the oxytocin receptor gene (OXTR) and the (clinical) implications for social behavior

Oxytocin and the oxytocin receptor (OXTR) play an important role in a large variety of social behaviors. The oxytocinergic system interacts with environmental cues and is highly dependent on interindividual factors. Deficits in this system have been linked to mental disorders associated with social impairments, such as autism spectrum disorder (ASD). This review focuses on the modulation of social behavior by alterations in two domains of the oxytocinergic system. We discuss genetic and epigenetic regulatory mechanisms and alterations in these mechanisms that were found to have clinical implications for ASD. We propose possible explanations how these alterations affect the biological pathways underlying the aberrant social behavior and point out avenues for future research. We advocate the need for integration studies that combine multiple measures covering a broad range of social behaviors and link these to genetic and epigenetic profiles.

Polymorphisms of dopamine receptor genes DRD2 and DRD4 in African populations of Hadza and Datoga differing in the level of culturally permitted aggression

The key regulator in the control of aggressive behavior is dopamine receptors. Association of variants in these genes with aggression has been shown in modern populations. However, these studies have not been conducted in traditional cultures. The aim of our study was to investigate population features in distributions of allele and genotype frequencies of DRD2 rs1800497, DRD4 120 bp Ins, and DRD4 exon III polymorphisms and their associations with aggressive behavior in the traditional African populations of Hadza and Datoga, which display a contrast in their culturally permitted aggression. Overall, 820 healthy unrelated Hadza and Datoga individuals were studied. Self-rated scores of aggression were collected using Buss and Perry's Aggression Questionnaire. Polymerase chain reaction-Restriction fragment length polymorphism (PCR-RFLP) was used to determine the genotype of each individual. We show that the Hadza and the Datoga differed significantly in allele and genotype frequencies of all studied loci. Our association analysis detected that only ethnicity and sex of individuals significantly influenced their aggression rank, but we failed to identify any associations of DRD2 rs1800497, DRD4 120 bp Ins, or DRD4 exon III polymorphisms with aggression. Thus, our data have no strong evidence to support the involvement of polymorphisms of DRD2 and DRD4 in controlling aggressive behavior.

Revisiting the impact of OXTR rs53576 on empathy: A population-based study and a meta-analysis

Oxytocin in the brain is related to empathy, which refers to the ability to understand and share others' internal states or responses. Previous studies have investigated the impact of OXTR rs53576, the most intensively examined polymorphism in the oxytocin receptor (OXTR) gene, on individual differences in empathy. However, these studies produced inconsistent results. In the current study, we reexamined the association of OXTR rs53576 with empathy in a relatively large population (N=1830) and also evaluated the association by a comprehensive meta-analysis (N=6631, 13 independent samples). The replication study indicated that OXTR rs53576 was indeed associated with individual differences in empathy. Individuals with a greater number of G alleles showed better empathic ability, particularly in fantasizing other's feelings and actions. The meta-analysis not only confirmed this association, but also indicated that the impact of this polymorphism was significant in both Europeans and Asians. These findings provide convincing evidence for the impact of OXTR rs53576 on empathy, highlighting the importance of OXTR gene in individuals' social cognition.

Associations between the oxytocin receptor gene (OXTR) rs53576 polymorphism and emotional processing of social and nonsocial cues: an event-related potential (ERP) study

Background

Oxytocin receptor (OXTR) gene polymorphisms are related to individual differences in emotional processing of social cues. However, whether OXTR polymorphisms affect emotional processing of nonsocial cues remains unclear. The present study investigated the relationship between the OXTR rs53576 polymorphism and emotional processing of social cues and nonsocial cues.

Methods

Event-related potentials were recorded from 88 male participants while images of humans and images of objects were presented as social cues and nonsocial cues, respectively.

Results

First, the results showed that GG carriers of OXTR rs53576 showed more negative N1 (50–200 ms) than AA carriers in response to images of both humans and objects. Second, GG carriers showed more negative N2 (200–320 ms) than AA carriers in response to images of humans but not in response to images of objects. Third, GG carriers showed more negative N2 in response to images of humans than images of objects, whereas AA carriers showed the opposite pattern. Fourth, we observed no difference in late positive potential (600–1000 ms) to images of humans or objects that depended on the OXTR rs53576 polymorphism.

Conclusions

These results suggest that the OXTR rs53576 polymorphism affects emotional processing of not only social cues but also nonsocial cues in the very early stage (reflected in N1); however, the data also suggest that the OXTR rs53576 polymorphism is related specifically to increased emotional processing of social cues in the middle stage (reflected in N2).