title: Reduced DNA methylation at the PEG3 DMR and KvDMR1 loci in children exposed to alcohol in utero: a South African Fetal Alcohol Syndrome cohort study.
abstract: Fetal alcohol syndrome (FAS) is a devastating developmental disorder resulting from alcohol exposure during fetal development. It is a considerable public health problem worldwide and is characterized by central nervous system abnormalities, dysmorphic facial features, and growth retardation. Imprinted genes are known to play an important role in growth and development and therefore four imprinting control regions (ICRs), H19 ICR, IG-DMR, KvDMR1 and PEG3 DMR were examined. It is proposed that DNA methylation changes may contribute to developmental abnormalities seen in FAS and which persist into adulthood. The participants included FAS children and controls from the Western and Northern Cape Provinces. DNA samples extracted from blood and buccal cells were bisulfite modified, the ICRs were amplified by PCR and pyrosequencing was used to derive a quantitative estimate of methylation at selected CpG dinucleotides: H19 ICR (six CpG sites; 50 controls and 73 cases); KvDMR1 (7, 55, and 86); IG-DMR (10, 56, and 84); and PEG3 DMR (7, 50, and 79). The most profound effects of alcohol exposure are on neuronal development. In this study we report on epigenetic effects observed in blood which may not directly reflect tissue-specific alterations in the developing brain. After adjusting for age and sex (known confounders for DNA methylation), there was a significant difference at KvDMR1 and PEG3 DMR, but not the H19 ICR, with only a small effect (0.84% lower in cases; p = 0.035) at IG-DMR. The two maternally imprinted loci, KvDMR1 and PEG3 DMR, showed lower average locus-wide methylation in the FAS cases (1.49%; p < 0.001 and 7.09%; p < 0.001, respectively). The largest effect was at the PEG3 DMR though the functional impact is uncertain. This study supports the role of epigenetic modulation as a mechanism for the teratogenic effects of alcohol by altering the methylation profiles of imprinted loci in a locus-specific manner.
authors: Division of Human Genetics, National Health Laboratory Service, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand , Johannesburg, South Africa.
authors: Matshane L
authors: ML
authors: Masemola
authors: Department of Statistics, Faculty of Natural Sciences, University of the Western Cape , Cape Town, South Africa ; Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University , Cape Town, South Africa.
authors: Lize
authors: L
authors: van der Merwe
authors: Division of Human Genetics, National Health Laboratory Service, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand , Johannesburg, South Africa ; Sydney Brenner Institute for Molecular Bioscience, University of the Witwatersrand , Johannesburg, South Africa ; School of Molecular and Cell Biology, Faculty of Science, University of the Witwatersrand , Johannesburg, South Africa.
authors: Zané
authors: Z
authors: Lombard
authors: Foundation for Alcohol Related Research , Cape Town, South Africa.
authors: Denis
authors: D
authors: Viljoen
authors: Division of Human Genetics, National Health Laboratory Service, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand , Johannesburg, South Africa ; Sydney Brenner Institute for Molecular Bioscience, University of the Witwatersrand , Johannesburg, South Africa.
authors: Michèle
authors: M
authors: Ramsay
keywords: H19 ICR; IG-DMR; KvDMR1; PEG3; epigenetics; fetal alcohol syndrome; imprinted genes