Job burnout is a stress-related syndrome influenced by both genetic and environmental factors. Poor sleep quality acting as a stressor may lead to job burnout. The oxytocin receptor gene (OXTR) related to stress reactivity may also exert an effect on job burnout. We aimed to explore the effect of sleep quality, a functional OXTR rs2268498 polymorphism, and their interaction on job burnout in the Chinese population, which has not been explored yet.
A preliminary study was performed using a cross-sectional design. The Pittsburgh Sleep Quality Index (PSQI) and the Malash Burnout Inventory (MBI) were measured from 575 healthy subjects. The OXTR rs2468498 polymorphism was genotyped in 376 subjects.
There were significant main effects of sleep quality (p<0.05), but not of the OXTR rs2468498 genotype on burnout. Interestingly, the interaction between sleep quality and the rs2468498 genotype was significant (p<0.05). In the poor sleep group, the C allele (C/C and T/C) carriers showed higher Emotional Exhaustion level than T homozygotes, while in the good sleep group, the C allele carrier showed a lower Emotional Exhaustion level.
This study covered subjects from only one university and the sample size for genotyping was relatively small. As we analyzed only the OXTR rs2268498 polymorphism, this study could not reveal the effects of the cerebrospinal oxytocin concentration and the haplotypes.
Our findings suggest that the OXTR polymorphism modulates the influence of subjective sleep quality on burnout. We conclude that the C allele of the OXTR rs2468498 polymorphism plays a susceptible role in job burnout.

Across species, the neuropeptide oxytocin has been associated with affiliative and social approach behavior. It has been suggested to exert its effects by modulating neural circuitry underlying anxiety, affiliative motivation, and social salience. The present study aims to investigate differences in subregional amygdala resting-state connectivity in healthy adult carriers of different genotypes of the oxytocin receptor (OXTR) gene polymorphism rs2268498. Previous studies have associated this polymorphic locus with social cognitive and affiliative phenotypes. The amygdala qualifies as a reasonable target due to its broad implication in emotional and social cognitive processing as well as its key role in mediating the behavioral effects of oxytocin. Whole brain seed-based functional connectivity analyses for the basolateral, centromedial and superficial amygdala revealed stronger resting-state connectivity of all amygdala subregions to the fusiform and inferior occipital gyrus in TT-carriers compared to C-allele carriers. Additional modulations were found for the centromedial amygdala which showed stronger resting-state connectivity to inferior frontal regions and the insula in C-allele carriers and to brainstem regions in TT-carriers. Our findings not only show the importance of oxytocin functioning in amygdalar neuronal signaling but also emphasize the need to investigate the amygdalar subregions individually instead of the amygdala as a whole. In summary, the present study is the first to characterize the impact of genetic variation of the OXTR gene with known functional consequences on widespread changes in a functional brain network originating from the amygdala.

There is increasing evidence for associations between polymorphisms of the oxytocin receptor (OXTR) gene and autism spectrum disorder, but to date no study has established links with autistic traits in healthy subjects and potential cultural differences. The present research firstly investigated associations between three widely studied OXTR SNPs and autistic and empathic traits (rs53576 (G/A); rs2254298 (G/A); rs2268498 (T/C)) in two independent studies on male and female Caucasian (n = 537) and Chinese students (n = 280). Autistic and empathic traits were measured in all subjects in the two independent groups using the Autism -Spectrum Quotient (AQ) and the Interpersonal Reactivity Index (IRI) respectively, together with their sub-scales. For both sites, genotyping of the OXTR SNPs was conducted on buccal swab samples using a Cobas Z 480 Light Cycler following automated DNA extraction. Associations at the genotype level with autism trait scores were found in Caucasian subjects for rs2268498 only, with TT carriers having the lowest AQ scores compared with those carrying at least one C-allele. This finding was independently replicated in the Chinese sample although a smaller proportion carried the C-allele compared with the Caucasian sample. Some minor associations were found between empathy trait scores and the three SNPs but were not consistent between the samples. These findings show for the first time that the rs2268498 SNP localized in the promoter flanking region of the OXTR gene is associated with autistic traits in different ethnic/cultural groups. This provides further support for the role of the OXTR gene in relation to autism.

The oxytocin system plays a prominent role in social behavior across species, and numerous genetic studies in humans have reported associations between polymorphisms on the oxytocin receptor (OXTR) gene and phenotypes related to social cognition, affiliation, perspective taking, and sociability in healthy subjects and in patients with atypical social behavior, such as in autism spectrum disorders (ASD). Recently, the first study demonstrating altered agonist-induced OXTR internalization and recycling for the exonic variant rs35062132 emerged. Beside this, there has been no further demonstration of the functionality of the OXTR variants especially there does not exist any for the regulatory units. To address this gap in the literature, we tested the functionality of the promoter flanking single nucleotide polymorphism (SNP) rs2268498, which has proven an interesting candidate for predicting social behavior in recent association studies. Results of genetic expression analyses in human hippocampal tissue showed a twofold difference in messenger RNA transcription, dependent on the presence or absence of the C-allele. This finding was corroborated by cloning, i.e., in vitro reporter gene expression analysis after transfection of OXTR promoter plasmids into HEK-293 cells. Our results underline the importance of OXTR rs2268498 for genetic research in social behavior and ASD.