A pilot study suggests that screening sperm may help uncover potentially hazardous new genetic abnormalities and assist fertility specialists in preventing them from being passed on to kids. The findings point to a possible tool for improving fertility therapy outcomes.
New disease-causing mutations can emerge in sperm, and dads may unintentionally pass them on to their children during fertilisation. These mutations may result in miscarriages or the development of a congenital illness that neither parent possesses.
“Every male sperm contains up to dozens of these new mutations, some of which are potentially harmful,” says co-senior author Martin Breuss, Assistant Professor in the clinical genetics and metabolism section of the Department of Pediatrics, University of Colorado Anschutz Medical Campus, Colorado, US. “However, it is unclear if analysing sperm for such mutations may assist forecast or avoid the risk of transmission to their offspring.”
Three couples who were undergoing in-vitro fertilisation procedures volunteered to take part in the study. The researchers employed whole-genome sequencing to find new mutations in each man’s sperm samples. They next looked for these alterations in preimplantation embryos from each partner at a very early stage of development.
The researchers discovered 55 mutations in the men’s sperm, 15 of which were passed on to an embryo. More than one of a couple’s embryos contained one of the mutations in certain situations, resulting in 19 incidences of transmission. The scientists predicted that mutations would be passed on to embryos less frequently than they were.
“Our findings demonstrate that novel sperm mutations may be transferred to embryos,” explains co-lead author Xiaoxu Yang, a postdoctoral fellow at the University of California, San Diego in the United States. “Preimplantation genetic testing of embryos might be used to choose embryos that did not get one of the dangerous new mutations discovered in their father’s sperm.”
Previous research by this group revealed that one in every 300 infants produced through IVF have a bad pregnancy result or poor health due to a new mutation in their father’s sperm.
“If larger studies confirm our findings, this new approach could result in more positive outcomes for families dealing with infertility by assisting in the prevention of pregnancy loss or congenital diseases,” says senior author Joseph Gleeson, Director of Neurodevelopmental Genetics and endowed chair of Rady Children’s Institute for Genomic Medicine in San Diego, California, US.