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Differential DNA methylation in peripheral blood mononuclear cells in adolescents exposed to significant early but not later childhood adversity

Published online by Cambridge University Press:  05 February 2016

Elisa A. Esposito
Affiliation:
University of Minnesota Institute of Child Development Widener University
Meaghan J. Jones
Affiliation:
University of British Columbia Child and Family Research Institute
Jenalee R. Doom
Affiliation:
University of Minnesota Institute of Child Development
Julia L MacIsaac
Affiliation:
University of British Columbia Child and Family Research Institute
Megan R. Gunnar*
Affiliation:
University of Minnesota Institute of Child Development
Michael S. Kobor
Affiliation:
University of British Columbia Child and Family Research Institute University of British Columbia
*
Address correspondence and reprint requests to: Megan R. Gunnar, Institute of Child Development, University of Minnesota, 51 East River Road, Minneapolis, MN 55455; E-mail: gunnar@umn.edu.

Abstract

Internationally adopted adolescents who are adopted as young children from conditions of poverty and deprivation have poorer physical and mental health outcomes than do adolescents conceived, born, and raised in the United States by families similar to those who adopt internationally. Using a sample of Russian and Eastern European adoptees to control for Caucasian race and US birth, and nonadopted offspring of well-educated and well-resourced parents to control for postadoption conditions, we hypothesized that the important differences in environments, conception to adoption, might be reflected in epigenetic patterns between groups, specifically in DNA methylation. Thus, we conducted an epigenome-wide association study to compare DNA methylation profiles at approximately 416,000 individual CpG loci from peripheral blood mononuclear cells of 50 adopted youth and 33 nonadopted youth. Adopted youth averaged 22 months at adoption, and both groups averaged 15 years at testing; thus, roughly 80% of their lives were lived in similar circumstances. Although concurrent physical health did not differ, cell-type composition predicted using the DNA methylation data revealed a striking difference in the white blood cell-type composition of the adopted and nonadopted youth. After correcting for cell type and removing invariant probes, 30 CpG sites in 19 genes were more methylated in the adopted group. We also used an exploratory functional analysis that revealed that 223 gene ontology terms, clustered in neural and developmental categories, were significantly enriched between groups.

Type
Regular Articles
Copyright
Copyright © Cambridge University Press 2016 

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