Abstract
BACKGROUND: Low birth weight is associated with an increased adult metabolic disease risk. It is widely discussed that poor intra-uterine conditions could induce long-lasting epigenetic modifications, leading to systemic changes in regulation of metabolic genes. To address this, we acquire genome-wide DNA methylation profiles from saliva DNA in a unique cohort of 17 monozygotic monochorionic female twins very discordant for birth weight. We examine if adverse prenatal growth conditions experienced by the smaller co-twins lead to long-lasting DNA methylation changes. RESULTS: Overall, co-twins show very similar genome-wide DNA methylation profiles. Since observed differences are almost exclusively caused by variable cellular composition, an original marker-based adjustment strategy was developed to eliminate such variation at affected CpGs. Among adjusted and unchanged CpGs 3153 are differentially methylated between the heavy and light co-twins at nominal significance, of which 45 show sensible absolute mean beta-value differences. Deep bisulfite sequencing of eight such loci reveals that differences remained in the range of technical variation, arguing against a reproducible biological effect. Analysis of methylation in repetitive elements using methylation-dependent primer extension assays also indicates no significant intra-pair differences. CONCLUSIONS: Severe intra-uterine growth differences observed within these monozygotic twins are not associated with long-lasting DNA methylation differences in cells composing saliva, detectable with up-to-date technologies. Additionally, our results indicate that uneven cell type composition can lead to spurious results and should be addressed in epigenomic studies.
Original language | English |
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Article number | 44 |
Number of pages | 15 |
Journal | Genome Biology |
Volume | 14 |
Issue number | 5 |
DOIs | |
Publication status | Published - 1 Jan 2013 |
Keywords
- LOW-BIRTH-WEIGHT
- BECKWITH-WIEDEMANN SYNDROME
- DEVELOPMENTAL ORIGINS
- FLOW-CYTOMETRY
- INFANT GROWTH
- HUMAN SALIVA
- IN-UTERO
- GENE
- RESTRICTION
- ASSOCIATION