title: Similar DNA methylation levels in specific imprinting control regions in children conceived with and without assisted reproductive technology: a cross-sectional study.
abstract: BACKGROUND
  While a possible link between assisted reproductive technology (ART) and rare imprinting disorders has been found, it is not clear if this is indicative of subtler disruptions of epigenetic mechanisms. Results from previous studies have been mixed, but some methylation differences have been observed.
  
  
  METHODS
  Children conceived through ART and children conceived spontaneously were recruited for this cross-sectional study. Information about reproductive history, demographic factors, birth characteristics, and infertility treatment was obtained from maternal interview and medical records. Peripheral blood lymphocytes and buccal cell samples were collected from participating children. Methylation analysis was performed on five loci using pyrosequencing. Statistical analysis of methylation differences was performed using linear regression with generalized estimating equations. Results are reported as differences with 95% confidence intervals (CI).
  
  
  RESULTS
  A total of 67 ART children and 31 spontaneously conceived (SC) children participated. No significant difference in methylation in lymphocyte samples was observed between groups for any loci. Possible differences were found in buccal cell samples for IGF2 DMR0 (Difference: 2.07; 95% confidence interval (CI): -0.28, 4.42; p = 0.08) and IGF2R (Difference: -2.79; 95% CI: -5.74, 0.16; p = 0.06). Subgroup analysis indicated potential lower methylation in those whose parents used ART for unexplained infertility.
  
  
  CONCLUSIONS
  Observed differences in methylation between the ART and SC groups were small for all loci in the two sample types examined and no statistical differences were observed. It is still unclear whether or not small differences observed in several studies represent a real difference between groups and if this difference is biologically meaningful. Larger studies with long term follow-up are needed to fully answer these questions.
authors.affiliation: Center for Health Outcomes and Prevention Research, Sanford Research, Sioux Falls, SD, USA. Susan.Puumala@sanfordhealth.org
authors.forename: Susan E
authors.initials: SE
authors.lastname: Puumala
authors.forename: Heather H
authors.initials: HH
authors.lastname: Nelson
authors.forename: Julie A
authors.initials: JA
authors.lastname: Ross
authors.forename: Ruby H N
authors.initials: RH
authors.lastname: Nguyen
authors.forename: Mark A
authors.initials: MA
authors.lastname: Damario
authors.forename: Logan G
authors.initials: LG
authors.lastname: Spector
mesh_terms: D000328:Adult; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D019175:DNA Methylation; D005260:Female; D005819:Genetic Markers; D018392:Genomic Imprinting; D006801:Humans; D007335:Insulin-Like Growth Factor II / Q000235:genetics; D016014:Linear Models; D008214:Lymphocytes; D008297:Male; D009061:Mouth Mucosa / Q000166:cytology; D024642:Potassium Channels, Voltage-Gated / Q000235:genetics; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; D017527:Receptor, IGF Type 2 / Q000235:genetics; D027724:Reproductive Techniques, Assisted; D017422:Sequence Analysis, DNA
chemical_list: D005819:Genetic Markers; C094335:H19 long non-coding RNA; C035170:IGF2 protein, human; D024642:Potassium Channels, Voltage-Gated; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; D017527:Receptor, IGF Type 2; D007335:Insulin-Like Growth Factor II