The role of TPH2 variant rs4570625 in shaping infant attention to social signals

TPH2, the rate-limiting enzyme in the synthesis of serotonin, has been connected to several psychiatric outcomes. Its allelic variant, rs4570625, has been found to relate to individual differences in cognitive and emotion regulation during infancy with T-carriers of rs4570625 showing a relatively heightened attention bias for fearful faces. A significant gene-environment interaction was also reported with the T-carriers of mothers with depressive symptoms showing the highest fear bias.We investigated these associations in a sample of 8-month old infants (N = 330), whose mothers were prescreened for low/high levels of prenatal depressive and/or anxiety symptoms. Attention disengagement from emotional faces (neutral, happy, fearful, and phase-scrambled control faces) to distractors was assessed with eye tracking and an overlap paradigm. Maternal depressive symptoms were assessed at several time points during pregnancy and postpartum. The mean levels of symptoms at six months postpartum and the trajectories of symptoms from early pregnancy until six months postpartum were used in the analyses (N = 274).No main effect of the rs4570625 genotype on attention disengagement was found. The difference in fear bias between the genotypes was significant but in an opposite direction compared to a previous study. The results regarding the interaction of the genotype and maternal depression were not in accordance with the previous studies.These results show inconsistencies in the effects of the rs4570625 genotype on attention biases in separate samples of infants from the same population with only slight differences in age.     

Association between serotonin Cumulative Genetic Score and the Behavioral Approach System (BAS): Moderation by early life environment

The present study investigates if genetic variation in the serotonergic system interacts with early adversity to predict changes in the Behavioral Approach System (BAS), a system that taps into reward processing. In a sample of community adults (N = 236) the influence of single serotonergic candidate polymorphisms on BAS was analyzed, we also examined the aggregate contribution of these genetic variants by creating a Cumulative Genetic Score (CGS). A CGS quantifies an individual’s cumulative risk by aggregating the number of risk alleles across the candidate polymorphisms. After individual gene analysis, three candidate genes rs7305115 (TPH2), rs6311 (HTR2A), and rs6295 (HTR1A) were combined into the CGS. There were no significant interactions between individual candidate polymorphisms and childhood adversity, but the CGS interacted with childhood adversity to explain a significant amount of variance (11.6%) in the BAS. Findings suggest that genetic variations in the serotonergic system in combination with childhood adversity contribute to individual differences in reward sensitivity.     

早期成长与发展研究：利用前瞻性的养子女设计研究遗传与环境的互动

“早期成长与发展研究”（EGDS）是一个前瞻性的养子女研究计划。此项目包括了360组相连的生身父母、养父母以及刚出生就被收养的子女。此项目从婴儿3个月就开始跟踪这些被试,现在又加上200组被试,从遗传与环境的关联与互动着手,本项目将研究家庭环境和养育方式如何影响遗传因素的表达。所有被试均需要是在美国国内收养的婴儿。该研究收集了儿童的心理特征、生身父母与养父母的心理特征、养育方式、父母的生活状况等数据,以及唾液和DNA,初步分析发现,遗传与环境的互动在婴儿期就已经开始。本文也从干预的角度讨论了未来行为遗传学的走向     

Stress-sensitivity and reciprocal associations between stressful events and adolescent temperament

This study aimed to elucidate the longitudinal, bidirectional associations between stressful life events (SLEs) and adolescent temperament. Subsequently, the study investigated whether the effects of SLEs on future temperament were moderated by (a) a cumulative sensitivity gene index (b) the 5-HTTLPR (the polymorphism most consistently indicated as a sensitivity genotype) and (c) pre/perinatal risk. Data were used from TRAILS, a large population cohort of Dutch adolescents (n = 1475). Temperament was assessed at 11, 16 and 19 years. Data of SLEs that occurred between age 0–11, 11–16, and 16–19 were captured using interviews. The results indicated that SLEs and temperament traits are associated from childhood to adolescence and that the direction of the effects differed between temperament traits. Whereas SLEs were found to predict subsequent fear, SLEs were predicted by, but not predictive of, shyness and affiliation. For effortful control and frustration a fully reciprocal model was found. The cumulative sensitivity gene index, 5-HTTLPR and the pre/perinatal risk did not moderate the effects of SLEs on future temperament.