Assisted Reproduction Treatments May Cause Imprinting Problems

January 26, 2012 These days, there is more than one way to make a baby. Unfortunately though, the newer ways still don’t have things down to a science yet. Assisted reproduction treatments (or technology, known as ART) are clinical procedures designed to help patients with fertility issues get pregnant. But reports have documented a rise in cases of Beckwith–Wiedemann Syndrome (BWS), an imprinting disorder characterized by unnatural growth patterns in children conceived by methods like in vitro fertilization. So P. de Boer at the Radboud University Nijmegen Medical Center in the Netherlands and colleagues scoured the scientific literature for data on the connections between ART and epigenetic effects in humans and mice.

de Boer’s review found, among other things, that:

• In mice, ART affects CpG methylation. The placenta, rather than the embryo, appears to be most vulnerable.
• Ovulation induction for in vitro fertilization has several effects on imprinting. It may be worth seeing if milder procedures help reduce the number of BWS cases.
• Improper spermatogenesis in humans affects sequence-specific DNA hypomethylation. These aberrant sperm could pass on paternal methylation abnormalities but the chances seem to be small.
• Imprinting differences in genes involved in metabolism are thought to cause low-birth-weights and chronic diseases, like cardiovascular diseases and diabetes mellitus.
• Some evidence hints that fertility issues themselves may indicate susceptibility for imprinting diseases.

The authors conclude that ART can cause epigenetic changes in offspring conceived by those methods. While they note mice have been better studied than humans in understanding ART’s influence on epigenetic inheritance, the authors say both species could benefit from genome-wide epigenetic profiling studies involving the different types of ART.

Pick up the rest of the details at Human Reproduction Update, January 2012.