Serotonin transporter gene methylation and emotional regulation in preschool children born preterm: A longitudinal evaluation of the role of negative emotionality in infancy

The aim of the study was to assess the contribution of negative emotionality at 3 months (T1) and serotonin transporter gene (SLC6A4) DNA methylation at 4.5 years of age (T2) to emotion regulation in pre-schoolers born very preterm and full-term. Forty one children (n = 21 born very preterm, n = 20 born full-term) participated in the study. Fretful behavior was assessed at T1 in response to the Face-to-FaceStill-Face (FFSF) paradigm. At T2, SLC6A4 DNA methylation was analyzed and emotion regulation was assessed using an observational procedure (i.e., the Pre-schooler Regulation of Emotional Stress, PRES). The very preterm group displayed higher emotion dysregulation during the PRES Reactivity phase than the full-term group. Higher levels of fretful behavior at 3 months were associated with greater emotional distress only for very preterm children with higher methylation at T2. No significant associations emerged in the full-term group. Despite current findings cannot be generalized owing to the relatively small sample size, this work provides preliminary longitudinal evidence about the link between negative emotionality during infancy, stress-linked epigenetic status at 4.5 years and emotion dysregulation in preschoolers born preterm.