Epigenetic Discordance at Imprinting Control Regions in Twins

Abstract

Imprinting control regions are differentially methylated in a parent-of-origin-dependent manner and this methylation state is inherited through the germline. These regions control parent-specific monoallelic expression of their target genes. Genetically identical organisms show considerable variation in their epigenomes owing to environmental and stochastic influences creating fluctuations in phenotype. Monozygotic twin pairs discordant for imprinting disorders due to epigenetic changes at imprinting control regions are an example of phenotypic variation caused by extreme variations of the epigenome. Here, we discuss the within-pair epigenetic discordance at imprinted loci, both in phenotypically concordant and discordant monozygotic twin pairs.

KEYWORDS::

• assisted reproductive technologies
• differentially methylated region
• DNA methylation
• genomic imprinting
• imprinting control region
• monozygotic twins
• twinning

Acknowledgements

The authors thank Trevelyan R Menheniott for critical reading of the manuscript.

Financial & competing interests disclosure

This work was supported by grants from the Australian National Health and Medical Research Council (grant numbers 437015 and 607358 to Jeffrey M Craig), the Sigrid Juselius Foundation (to Miina Ollikainen), the Academy of Finland (to Miina Ollikainen), and the Finnish Cultural Foundation (to Miina Ollikainen). 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.

Additional information

Funding

This work was supported by grants from the Australian National Health and Medical Research Council (grant numbers 437015 and 607358 to Jeffrey M Craig), the Sigrid Juselius Foundation (to Miina Ollikainen), the Academy of Finland (to Miina Ollikainen), and the Finnish Cultural Foundation (to Miina Ollikainen). 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.