Effects of Genotype and Sleep on Temperament

Abstract

, on behalf of the MAVAN research team abstract BACKGROUND AND OBJECTIVES: Sleep problems are frequent in young children; however, children vary in the degree to which they are affected by poor sleep quality. We investigated whether a polymorphism in the serotonin transporter gene, which is linked to emotional function, is a potential moderator of the influences of sleep duration on infant temperament using longitudinal data. METHODS:We examined the interactive effects of average sleep duration between 6 and 36 months of age and the 5-HTTLPR genotype on negative emotionality/behavioral dysregulation at 36 months in 209 children recruited into a longitudinal birth cohort study. Triallelic genotyping of 5-HTTLPR was performed by looking at SLC6A4 genotype, focusing on the serotonin transporter-linked polymorphic region (5-HTTLPR) including the SNP polymorphism (rs23351). Child sleep habits were assessed with a maternal self-report questionnaire.RESULTS: After controlling for demographics and both previous and concurrent maternal depression, multiple linear regression analyses revealed a significant interaction effect of average sleep duration for the first 3 years of life and 5-HTTLPR genotype on child negative emotionality/behavioral dysregulation such that the effects were exclusive to those with low-expressing 5-HTTLPR genotypes. CONCLUSIONS:The results suggest differential susceptibility to the effect of sleep duration early in life, which reiterates that the short allele of the 5-HTTLPR represents a marker of increased environmental sensitivity regarding emotional development. Differential susceptibility theory posits that certain factors may increase an individual's susceptibility to the environment, in either a positive or negative fashion. WHAT'S KNOWN ON THIS SUBJECT:Sleep disturbances in infants associate with individual differences in temperament. However, little is known about interindividual differences and potential moderating factors, such as genotype. WHAT THIS STUDY ADDS:The results suggest that the cumulative effect of total sleep duration during the first 3 years of life on temperament is moderated by child 5-HTTLPR genotype following a differential susceptibility model.

Parent-reported early sleep problems and internalising, externalising and dysregulation symptoms in toddlers

“…In other words, individual variability in sleep-wake behaviour problems has been linked to affect and emotions through hypothesised shared central nervous system to sleep and the neurobehavioural systems underlying arousal and emotions 31 32. In accordance with this assumption, difficult temperament33 and genetic factors34 are related to both sleeping and emotional problems in children. Second, sleep and emotional problems may be explained by the same environmental factors.…”

Sleep and its relation to cognition and behaviour in preschool‐aged children of the general population: a systematic review

“…() found in their study that treatment of sleep disturbance improved daytime behaviour. New findings also report a differential role of sleep according to the child's genotype (Bouvette‐Turcot et al ., ). Our present understanding in this field could be greatly improved by these innovative research approaches.…”

Sleep-wake behaviour during the first 12 months of life and associated factors: a systematic review

“…Effects of sleep-wake behaviour were less studied, but worse sleep-wake behaviour were shown to predict later social-emotional (Bernier et al, 2010;Bordeleau et al, 2012;Bouvette-Turcot et al, 2015;Sadeh et al, 2015;Saenz et al, 2015), and sleep problems (Byars et al, 2012;Hysing et al, 2014;Palmstierna et al, 2008;Tikotzky & Shaashua, 2012).…”

“…This may indicate that early sleep-wake behaviour is associated with brain maturation (Saenz et al, 2015). Authors of a recent study stated the importance of differential susceptibility in the association between sleep duration and later emotional development, reporting that this association is only present in infants with 5-HTTLPR allele (Bouvette-Turcot et al, 2015). Sleep-wake behaviour was not associated with externalizing problems in 1 study, whose results suggested, however, that sleep duration during the night moderated the association between maternal sensitivity and internalizing/externalizing symptoms (Bordeleau et al, 2012).…”