Study suggests a potential tool to help improve fertility treatment outcomes

Sperm screening can help identify potentially harmful new genetic mutations and help fertility specialists prevent them from being passed on to offspring, according to a preliminary study published in eLife.

The results suggest a possible tool to improve the outcomes of fertility treatment.

New harmful disease-causing mutations can arise in sperm, and fathers can accidentally pass them on to their offspring during conception. These mutations can cause miscarriages or lead to a child developing a congenital disease that neither parent has.

Each male houses up to dozens of these new mutations in their sperm, some of which are potentially harmful. But whether testing sperm for such mutations can help predict or prevent the risk of transmission to their children is unclear. “

Martin Breuss, Associate Professor, Assistant Professor in the Department of Clinical Genetics and Metabolism of the Department of Pediatrics, University of Colorado Anschutz Medical Campus, Colorado, USA

Three couples who underwent in vitro fertilization treatments agreed to participate in the research. The researchers used whole genome sequencing to detect new mutations in each man’s sperm samples. They then tested pre-implantation embryos at a very early stage of development of each pair for these mutations.

The team identified 55 mutations in the men’s sperm, including 15 that were transferred to an embryo. In some cases, more than one of a couple’s embryos had one of the mutations that resulted in 19 cases of transmission. Mutations were transferred to the embryos slightly less frequently than the authors expected.

“Our results confirm that new mutations in sperm can be transferred to embryos,” said co-author Xiaoxu Yang, a postdoctoral fellow at the University of California, San Diego, USA. “Pre-implantation genetic testing of embryos can be used to select embryos that have not received any of the harmful new mutations detected in their father’s sperm.”

Previous studies by this team have suggested that one in 300 children conceived by in vitro fertilization has a poor pregnancy outcome or poor health caused by a new mutation in their father’s sperm.

“If larger studies confirm our findings, this new approach could lead to more positive outcomes for families struggling with infertility by helping prevent pregnancy loss or congenital diseases,” concludes senior author Joseph Gleeson, Director of Neuro-Developmental Genetics and Gifted Chair of Rady Children’s Institute for Genomic Medicine in San Diego, California, USA.


Journal reference:

Breuss, MW, et al. (2022) Unbiased mosaic variant assessment in sperm: a cohort study to test the predictability of transfer. eLife.

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