lunes, 26 de marzo de 2012

PLoS ONE: DNA Methylation Patterns in Cord Blood DNA and Body Size in Childhood

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PLoS ONE: DNA Methylation Patterns in Cord Blood DNA and Body Size in Childhood


DNA Methylation Patterns in Cord Blood DNA and Body Size in Childhood


Caroline L. Relton1, Alexandra Groom1*, Beate St. Pourcain2, Adrian E. Sayers3, Daniel C. Swan4, Nicholas D. Embleton5,6, Mark S. Pearce6, Susan M. Ring7, Kate Northstone2, Jon H. Tobias3, Joseph Trakalo8, Andy R. Ness9, Seif O. Shaheen10, George Davey Smith2
1 HNRC, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom, 2 MRC Centre for Causal Analyses in Translational Epidemiology, University of Bristol, Bristol, United Kingdom, 3 Musculoskeletal Research Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom, 4 Bioinformatic Support Unit, Newcastle University, Newcastle upon Tyne, United Kingdom, 5 Newcastle Neonatal Service, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom, 6 Institute of Health and Society, Newcastle University, Newcastle upon Tyne, United Kingdom, 7 School of Social and Community Medicine, University of Bristol, Bristol, United Kingdom, 8 Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom, 9 School of Dental Sciences, University of Bristol, Bristol, United Kingdom, 10 Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom

Abstract 

Background

Epigenetic markings acquired in early life may have phenotypic consequences later in development through their role in transcriptional regulation with relevance to the developmental origins of diseases including obesity. The goal of this study was to investigate whether DNA methylation levels at birth are associated with body size later in childhood.

Principal Findings

A study design involving two birth cohorts was used to conduct transcription profiling followed by DNA methylation analysis in peripheral blood. Gene expression analysis was undertaken in 24 individuals whose biological samples and clinical data were collected at a mean ± standard deviation (SD) age of 12.35 (0.95) years, the upper and lower tertiles of body mass index (BMI) were compared with a mean (SD) BMI difference of 9.86 (2.37) kg/m2. This generated a panel of differentially expressed genes for DNA methylation analysis which was then undertaken in cord blood DNA in 178 individuals with body composition data prospectively collected at a mean (SD) age of 9.83 (0.23) years. Twenty-nine differentially expressed genes (>1.2-fold and p<10−4) were analysed to determine DNA methylation levels at 1–3 sites per gene. Five genes were unmethylated and DNA methylation in the remaining 24 genes was analysed using linear regression with bootstrapping. Methylation in 9 of the 24 (37.5%) genes studied was associated with at least one index of body composition (BMI, fat mass, lean mass, height) at age 9 years, although only one of these associations remained after correction for multiple testing (ALPL with height, pCorrected = 0.017).

Conclusions

DNA methylation patterns in cord blood show some association with altered gene expression, body size and composition in childhood. The observed relationship is correlative and despite suggestion of a mechanistic epigenetic link between in utero life and later phenotype, further investigation is required to establish causality.

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