title: Extreme methylation values of imprinted genes in human abortions and stillbirths.
abstract: Imprinted genes play an important role in fetal and placental development. Using quantitative bisulfite pyrosequencing assays, we determined the DNA methylation levels at two paternally methylated (H19 and MEG3) and four maternally methylated (LIT1, NESP55, PEG3, and SNRPN) imprinted regions in fetal muscle samples from abortions and stillbirths. Two of 55 (4%) spontaneous abortions and 10 of 57 (18%) stillbirths displayed hypermethylation in multiple genes. Interestingly, none of 34 induced abortions had extreme methylation values in multiple genes. All but two abortions/stillbirths with multiple methylation abnormalities were male, indicating that the male embryo may be more susceptible to excess methylation. Hypermethylation of multiple imprinted genes is consistent with stochastic failures of the mechanism, which normally protects the hypomethylated allele from de novo methylation after fertilization. Two of six informative abortions/stillbirths with H19 hypermethylation revealed significant biallelic expression of the autocrine growth factor IGF2. In two other cases hypermethylation of MEG3 was associated with transcriptional down-regulation. We propose that primary epimutations resulting in inappropriate methylation and expression patterns of imprinted genes may contribute to both normal human variation and disease, in particular spontaneous pregnancy loss.
authors.affiliation: Institute of Human Genetics, Department of Pediatric Pathology, Johannes Gutenberg University, Mainz, Germany.
authors.forename: Galyna
authors.initials: G
authors.lastname: Pliushch
authors.forename: Eberhard
authors.initials: E
authors.lastname: Schneider
authors.forename: Daniela
authors.initials: D
authors.lastname: Weise
authors.forename: Nady
authors.initials: N
authors.lastname: El Hajj
authors.forename: Achim
authors.initials: A
authors.lastname: Tresch
authors.forename: Larissa
authors.initials: L
authors.lastname: Seidmann
authors.forename: Wiltrud
authors.initials: W
authors.lastname: Coerdt
authors.forename: Annette M
authors.initials: AM
authors.lastname: Müller
authors.forename: Ulrich
authors.initials: U
authors.lastname: Zechner
authors.forename: Thomas
authors.initials: T
authors.lastname: Haaf
mesh_terms: D000028:Abortion, Induced; D019175:DNA Methylation / Q000235:genetics*; D005260:Female; D005333:Fetus / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018392:Genomic Imprinting / Q000235:genetics*; D006801:Humans; D009132:Muscles / Q000378:metabolism; D011247:Pregnancy; D050497:Stillbirth / Q000235:genetics*