Identical Twins Doubly Exchanged at Birth: A Case Report of Genetic and Environmental Influences on the Adult Epigenome

Abstract

Aim: Epigenetic comparisons within monozygotic twin pairs have enhanced our understanding of nongenetic mechanisms underlying disease etiology. We present epigenetic findings for a unique case of doubly exchanged Colombian male monozygotic twins raised in extremely different environments. Results: Using genome-wide DNA methylation data from cheek swabs from which blood-specific differentially methylated probes had been removed, the individuals grouped by shared genetics rather than shared environment, except for one twin who presented as an outlier. Closer inspection of DNA methylation differences within both reared-apart twin pairs revealed several genes and genetic pathways likely to be influenced by the rearing environment. Conclusion: Together with our previous findings, we suggest that genetics, pre- and postnatal environments contribute to the epigenetic profile, although additional studies are needed to quantify these effects.

Keywords::

• epigenetics
• genetics
• genome-wide DNA methylation
• monozygotic twins reared apart

Supplementary data

To view the supplementary data that accompany this paper please visit the journal website at: http://www.tandfonline.com/doi/full/10.2217/nnm-2016-0104

Acknowledgements

The authors wish to thank the five individuals in this case report for their contributions and JH Eric Joo from the Department of Pathology, University of Melbourne, for generating Infinium array data.

Author contributions

N Segal had the idea for the study, gathered the saliva samples from the five participants and forwarded them to the lab of JM Craig and YJ Loke. Y Montoya assisted in the collection of the saliva samples. YJ Loke and JM Craig performed the analyses and data interpretations. All authors contributed written sections of the manuscript based on their areas of expertise. All authors read and approved the final manuscript.

Financial & competing interests disclosure

This study was supported by an intramural research grant and an Open Access Publication Fund Grant to the first author (CSU Fullerton), a book advance to the first two authors (St. Martin’s Press, NY, USA) and by the Victorian State Government’s Operational Infrastructure Support Program (YJ Loke and JM Craig). The funding bodies had no role in the study design, analysis, data interpretation or writing of this manuscript. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Ethics approval and participant consent

This project was approved by the IRB of California State University, Fullerton, where the first author is a faculty member. The five human subjects all signed consent forms prior to this research, as required by the university. As indicated above, the five participants in this case study signed consent forms agreeing to the research. The consent form was approved in advance by the IRB at CSU Fullerton.

Additional information

Funding

This study was supported by an intramural research grant and an Open Access Publication Fund Grant to the first author (CSU Fullerton), a book advance to the first two authors (St. Martin’s Press, NY, USA) and by the Victorian State Government’s Operational Infrastructure Support Program (YJ Loke and JM Craig). The funding bodies had no role in the study design, analysis, data interpretation or writing of this manuscript. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. No writing assistance was utilized in the production of this manuscript.