Published online by Cambridge University Press: 14 August 2017
Although infants less than 18 months old are capable of engaging in self-regulatory behavior (e.g., avoidance, withdrawal, and orienting to other aspects of their environment), the use of self-regulatory strategies at this age (as opposed to relying on caregivers) is associated with elevated behavioral and physiological distress. This study investigated infant dopamine-related genotypes (dopamine receptor D2 [DRD2], dopamine transporter solute carrier family C6, member 4 [SLC6A3], and catechol-O-methyltransferase [COMT]) as they interact with maternal self-reported history of maltreatment to predict observed infant independent emotion regulation behavior. A community sample (N = 193) of mother–infant dyads participated in a toy frustration challenge at infant age 15 months, and infant emotion regulation behavior was coded. Buccal cells were collected for genotyping. Maternal maltreatment history significantly interacted with infant SLC6A3 and COMT genotypes, such that infants with more 10-repeat and valine alleles of SLC6A3 and COMT, respectively, relative to infants with fewer or no 10-repeat and valine alleles, utilized more independent (i.e., maladaptive) regulatory behavior if mother reported a more extensive maltreatment history, as opposed to less. The findings indicate that child genetic factors moderate the intergenerational impact of maternal maltreatment history. The results are discussed in terms of potential mechanism of Gene × Environment interaction.
This research was supported by funds from the Canadian Institutes of Health Research (MOP-64301), Ryerson University, and the Centre for Addiction and Mental Health. The authors acknowledge the contributions of Dr. Susan Goldberg, a Co-Principal Investigator on the grant that supported this work. She died prior to completion of the project, but her influence pervades the manuscript. We thank Emilie Boucher and Monica Tan, as well as other research assistants and students who contributed a great many hours to this project. Of course, we also greatly appreciate the time and effort of the mothers and babies who volunteered to participate in this project.