Stability of epigenetic structures in ART children

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DESCRIPTION (provided by applicant): Involuntary infertility affects approximately one in ten couples, worldwide. This fraction of the population translates to a large number of individuals who are potential candidates for assisted reproductive technology (ART). In fact, more than a million children have been born as the result of in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) and children conceived by these procedures account for more than 1% of all births in several western countries. Despite the many reassuring reports on the safety of ART, there have been a small number of recent reports suggesting that ART children may be at increased risk for rare congenital malformation syndromes that are related to defects in genome imprinting. At least three children conceived by ICSI have been diagnosed with Angelman syndrome and at least 28 ART children (both IVF and ICSI cases) have been diagnosed with Beckwith-Wiedemann syndrome. The suggestion that ART children may be at modestly increased risk for rare, congenital disorders associated with defects in imprinting is troubling on two counts. The first is the obvious and direct impact of these particular syndromes on affected children and their families. The second, and more troubling, consideration is that these data may portend more widespread effects of ART on the establishment or maintenance of genome imprints, or other epigenetic marks, than can be assessed by screening for rare congenital abnormalities. For example, a strong association between sporadic colon cancer and constitutional loss of imprinting at the insulin-like growth factor 2 gene has been reported independently by two laboratories. The purpose of the proposed study is to determine whether ART increases the possibility of deregulated expression of imprinted genes and/or destabilizes epigenetic chromosomal marking. Seven measures of epigenetic chromosomal marking (DNA methylation at three differentially methylated regions, transcription of alleles at three imprinted genes, and X-chromosome inactivation ratios in females) will be analyzed on a population of 500 newborns conceived through ART and a control population of 500 newborns conceived in the traditional fashion. The incidence of abnormal epigenetic marks will be compared between the two populations to determine whether any aspect of the ART procedure results in destabilization of epigenetic structures in the genomes of early human embryos.