CLINICAL REPORT Aberrant Methylation of H19-DMR Acquired After Implantation Was Dissimilar in Soma Versus Placenta of Patients With Beckwith–Wiedemann Syndrome Ken Higashimoto, 1 Kazuhiko Nakabayashi, 2 Hitomi Yatsuki, 1 Hokuto Yoshinaga, 1 Kosuke Jozaki, 1 Junichiro Okada, 3 Yoriko Watanabe, 3 Aiko Aoki, 4 Arihiro Shiozaki, 4 Shigeru Saito, 4 Kayoko Koide, 1 Tsunehiro Mukai, 5 Kenichiro Hata, 2 and Hidenobu Soejima 1 * 1 Division of Molecular Genetics & Epigenetics, Department of Biomolecular Sciences, Faculty of Medicine, Saga University, Saga, Japan 2 Department of Maternal–Fetal Biology, National Research Institute for Child Health and Development, Setagaya, Tokyo, Japan 3 Department of Pediatrics, Kurume University, Kurume, Japan 4 Department of Obstetrics and Gynecology, University of Toyama, Toyama, Japan 5 Nishikyushu University, Kanzaki, Saga, Japan Manuscript Received: 7 October 2011; Manuscript Accepted: 19 January 2012 Gain of methylation (GOM) at the H19-differentially methylated region (H19-DMR) is one of several causative alterations in Beckwith–Wiedemann syndrome (BWS), an imprinting-related disorder. In most patients with epigenetic changes at H19-DMR, the timing of and mechanism mediating GOM is unknown. To clarify this, we analyzed methylation at the imprinting control regions of somatic tissues and the placenta from two unrelated, naturally conceived patients with sporadic BWS. Maternal H19-DMR was abnormally and variably hypermethylated in both patients, indicating epigenetic mosaicism. Aberrant methylation levels were consistently lower in placenta than in blood and skin. Mosaic and discordant methylation strongly suggested that aberrant hypermethylation occurred after implantation, when genome-wide de novo methylation normally occurs. We expect aberrant de novo hypermethylation of H19-DMR happens to a greater extent in embryos than in placentas, as this is normally the case for de novo methylation. In addition, of 16 primary imprinted DMRs analyzed, only H19-DMR was aberrantly methylated, except for NNAT DMR in the placental chorangioma of Patient 2. To our knowledge, these are the first data suggesting when GOM of H19-DMR occurs. Ó 2012 Wiley Periodicals, Inc. Key words: Beckwith–Wiedemann syndrome; H19-DMR; aberrant DNA methylation; after implantation INTRODUCTION Beckwith–Wiedemann syndrome (BWS) is an imprinting-related condition characterized by macrosomia, macroglossia, and abdominal wall defects (OMIM #130650). The relevant imprinted chromosomal region in BWS, 11p15.5, consists of two independent imprinted domains, IGF2/H19 and CDKN1C/KCNQ1OT1. Imprinted genes within each domain are regulated by two imprinting control regions (ICR), the H19-differentially methylated region (H19-DMR) or KvDMR1 [Weksberg et al., 2010]. Several causative alterations have been identified in patients with BWS: loss of methylation (LOM) at KvDMR1, gain of methylation (GOM) at H19-DMR, paternal uniparental disomy (UPD), CDKN1C mutations, and chromosomal abnormality involving 11p15 [Sasaki et al., 2007; Weksberg et al., 2010]. Additional supporting information may be found in the online version of this article. Grant sponsor: Japan Society for the Promotion of Science; Grant number: 20590330; Grant sponsor: Ministry of Health, Labor, and Welfare; Grant sponsor: National Center for Child Health and Development. *Correspondence to: Hidenobu Soejima, M.D., Ph.D., Professor, Division of Molecular Genetics & Epigenetics, Department of Biomolecular Sciences, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga 849-8501, Japan. E-mail: soejimah@med.saga-u.ac.jp Article first published online in Wiley Online Library (wileyonlinelibrary.com): 10 May 2012 DOI 10.1002/ajmg.a.35335 How to Cite this Article: Higashimoto K, Nakabayashi K, Yatsuki H, Yoshinaga H, Jozaki K, Okada J, Watanabe Y, Aoki A, Shiozaki A, Saito S, Koide K, Mukai T, Hata K, Soejima H. 2012. Aberrant methylation of H19-DMR acquired after implantation was dissimilar in soma versus placenta of patients with Beckwith–Wiedemann syndrome. Am J Med Genet Part A 158A:1670–1675. Ó 2012 Wiley Periodicals, Inc. 1670