title: Outlier DNA methylation levels as an indicator of environmental exposure and risk of undesirable birth outcome.
abstract: We have identified a novel molecular phenotype that defines a subgroup of newborns who have highly disrupted epigenomes. We profiled DNA methylation in cord blood of 114 children selected from the lowest and highest quintiles of the birth weight distribution (irrespective of their mode of conception) at 96 CpG sites in genes we have found previously to be related to birth weight or growth and metabolism. We identified those individuals in each group who differed from the mean of the distribution by the greatest magnitude at each site and for the largest number of sites. Such 'outlier' individuals differ substantially from the rest of the group in having highly disrupted methylation levels at many CpG sites. We find that children from the lowest quintile of the birth weight distribution have a significantly greater number of disrupted CpGs than children from the highest quintile of the birth weight distribution. Among children from the lowest quintile of the birth weight distribution, 'outlier' individuals are significantly more common among children conceived in vitro than children conceived in vivo. These observations are novel and potentially important because they associate a molecular phenotype (multiple and large DNA methylation differences) in normal somatic tissues (cord blood) with both a prenatal exposure (conception in vitro) and a clinically important outcome (low birth weight). These observations suggest that some individuals are more susceptible to environmentally mediated epigenetic alterations than others.
authors.affiliation: Fels Institute for Cancer Research and Molecular Biology.
authors.forename: Jayashri
authors.initials: J
authors.lastname: Ghosh
authors.affiliation: Department of Obstetrics & Gynecology, University of Pennsylvania School of Medicine, Philadelphia, PA 19119, USA.
authors.forename: Monica
authors.initials: M
authors.lastname: Mainigi
authors.affiliation: Department of Obstetrics & Gynecology, University of Pennsylvania School of Medicine, Philadelphia, PA 19119, USA sapienza@temple.edu ccoutifaris@uphs.upenn.edu.
authors.forename: Christos
authors.initials: C
authors.lastname: Coutifaris
authors.affiliation: Fels Institute for Cancer Research and Molecular Biology, Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA and sapienza@temple.edu ccoutifaris@uphs.upenn.edu.
authors.forename: Carmen
authors.initials: C
authors.lastname: Sapienza
mesh_terms: D001724:Birth Weight / Q000235:genetics*; D002648:Child; D018899:CpG Islands; D019175:DNA Methylation; D004781:Environmental Exposure; D044127:Epigenesis, Genetic; D005260:Female; D005307:Fertilization in Vitro; D005312:Fetal Blood; D006801:Humans; D008297:Male; D012307:Risk Factors