title: DNA methylation differences between in vitro- and in vivo-conceived children are associated with ART procedures rather than infertility.
abstract: BACKGROUND
  We, and others, have demonstrated previously that there are differences in DNA methylation and transcript levels of a number of genes in cord blood and placenta between children conceived using assisted reproductive technologies (ART) and children conceived in vivo. The source of these differences (the effect of ART versus the underlying infertility) has never been determined in humans. In this study, we have attempted to resolve this issue by comparing placental DNA methylation levels at 37 CpG sites in 16 previously identified candidate genes in independent populations of children conceived in vivo ('fertile control' group) with ART children conceived from two groups: either autologous oocytes with infertility in one or both parents ('infertile ART' group) or donor oocytes (obtained from young fertile donors) without male infertility ('donor oocyte ART' group).
  
  
  RESULTS
  Of the 37 CpG sites analyzed, significant differences between the three groups were found in 11 CpGs (29.73 %), using ANOVA. Tukey's post hoc test on the significant results indicated that seven (63.63 %) of these differences were significant between the donor oocyte ART and fertile control groups. In addition, 20 of the 37 CpGs analyzed had been identified as differentially methylated between ART and fertile control groups in an independent population in a prior study. Of these 20 CpG sites, 9 also showed significant differences in the present population. An additional 9 CpGs were found to be significantly different between the two groups. Of these 18 candidate CpGs, 12 CpGs (in seven candidate genes) also showed significant differences in placental DNA methylation levels between the donor oocyte ART and fertile control groups.
  
  
  CONCLUSIONS
  These data suggest strongly that the DNA methylation differences observed between ART and in vivo conceptions are associated with some aspect of ART protocols, not simply the underlying infertility.
authors.affiliation: Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, 3307 N Broad Street, Philadelphia, PA 19140 USA.
authors.forename: Sisi
authors.initials: S
authors.lastname: Song
authors.affiliation: Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, 3307 N Broad Street, Philadelphia, PA 19140 USA.
authors.forename: Jayashri
authors.initials: J
authors.lastname: Ghosh
authors.affiliation: Department of Obstetrics and Gynecology, University of Pennsylvania School of Medicine, 3701 Market Street, 8th Floor, Philadelphia, PA 19119 USA.
authors.forename: Monica
authors.initials: M
authors.lastname: Mainigi
authors.affiliation: Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, 3307 N Broad Street, Philadelphia, PA 19140 USA.
authors.forename: Nahid
authors.initials: N
authors.lastname: Turan
authors.affiliation: Department of Obstetrics and Gynecology, University of Pennsylvania School of Medicine, 3701 Market Street, 8th Floor, Philadelphia, PA 19119 USA.
authors.forename: Rachel
authors.initials: R
authors.lastname: Weinerman
authors.affiliation: Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, 3307 N Broad Street, Philadelphia, PA 19140 USA.
authors.forename: May
authors.initials: M
authors.lastname: Truongcao
authors.affiliation: Department of Obstetrics and Gynecology, University of Pennsylvania School of Medicine, 3701 Market Street, 8th Floor, Philadelphia, PA 19119 USA.
authors.forename: Christos
authors.initials: C
authors.lastname: Coutifaris
authors.affiliation: Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, 3307 N Broad Street, Philadelphia, PA 19140 USA ; Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia, PA 19140 USA.
authors.forename: Carmen
authors.initials: C
authors.lastname: Sapienza
keywords: Assisted reproduction; DNA methylation; Donor oocytes; Infertility; Placenta