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.

The Impact of Traditional Food and Lifestyle Behavior on Epigenetic Burden of Chronic Disease

“…Decreased DNA methylation and increased H4 acetylation in the ovary Alcohol Human/ cohort study Association between maternal alcohol and DNA methylation in whole blood/buccal tissues of children (1-16 years) [265,267] Hypomethylation of the KvDMR1 and PEG3 DMR Differential methylation of 269 CpGs on multiple genes related to protocadherins, glutamatergic synapses, and hippocampal signaling Human/ cohort study Association between periconceptional alcohol use in parents and cord blood methylation levels [266] Hypomethylation of the DAT gene promoter due to maternal (before and during pregnancy) and paternal (before conception) alcohol use…”

“…Increasing body of evidence indicates that epigenetic alterations may underlie the changes characteristic of fetal alcohol syndrome. [264] Prenatal exposure to alcohol is demonstrated to induce extensive DNA methylation changes in human [265][266][267] and rodent offsprings ( Table 2). [110,112,114,120,128,[268][269][270][271][272] These effects are possibly transmitted via methylation of the paternal germ line, [273] although alcohol-induced placental epigenetic changes suggest the involvement of the female germ line.…”

Alcohol-Induced Developmental Origins of Adult-Onset Diseases

“…Since this initial work, other studies have identified heritable alterations in chromatin structure arising from early gestational exposures, suggesting epigenetic mechanisms are relevant to the development of FASDs (Chen et al, 2013, Veazey et al, 2015, Zhang et al, 2015, Marjonen et al, 2015). As an example, studies examining blood samples derived from FAS children have demonstrated altered DNA methylation within the regulatory regions of select imprinted genes, suggesting that alcohol-induced alterations in chromatin structure may persist through development and into early adulthood (Laufer et al, 2015, Masemola et al, 2015). Interestingly, recent work suggests some of these epigenetic lesions may transmit through the male germline into the next generation (Govorko et al, 2012).…”

Prenatal exposures and DNA methylation in newborns: a pilot study in Durban, South Africa

“…To date, epigenetic epidemiological studies of mothers and children in Sub-Saharan Africa have identified differentially methylated genes in rural Gambian babies and children associated with periconceptual nutrition status (8–11) or maternal aflatoxin exposure during pregnancy (12). In South African, children with fetal alcohol syndrome had altered methylation at imprinted genes compared with healthy children (13). In the Democratic Republic of Congo, maternal stress from ongoing war was associated with differential methylation – including at key genes involved in stress response – among newborns and their mothers (14–16).…”