Japanese scientists have discovered that a single mutation in a gene could lead to infertility in humans and not through a disruption of the production of egg or sperm cells but rather by leading to abnormalities in the morphology of the sexual organs – making natural reproduction impossible.
The beta-catenin gene codes a protein known to be deeply involved in a number of developmental and homeostatic processes. It is an essential protein, which has been shown in mice to be involved in the development and maintenance of most, if not all organs, throughout their lives.
Normally, it is switched on at some points during development, but then is turned off when it is no longer appropriate. The team from the RIKEN BioResource Center (BRC) in Tsukuba, Japan, developed a mouse with a single mutation to the beta-catenin gene.
They found the mice were not able to produce offspring through natural mating but were able to do so through in-vitro fertilisation, showing that the problem was caused by a structural problem rather than a problem with the eggs or sperm.
“This could lead to a path for the early detection and treatment based on the genetic diagnosis of the infertility,” concluded Yoichi Gondo, who led the research group.
This research could help to deepen our understanding of infertility—a problem that troubles almost one in ten couples today hoping to have a baby. The research has also elucidated a new function for the Wnt/beta-catenin pathway, which plays a role in regulating cell growth as well as cell-cell communication.
Takuya Murata of RIKEN BRC, the first author of the paper, says, “Because the amino acid sequence of beta-catenin is 100% identical in humans and mice, the nucleotide change we saw could cause the same mutation in humans. This raises the possibility that some infertility could be caused by B-catenin, which has not generally been considered as a potential cause so far.
“This finding came as a major surprise because we were expecting to see effects on many organs, since the Wnt/beta-catenin pathway is so ubiquitous. But instead we found that the effects of this change were limited to specific organs.”
Yoichi Gondo, who led the research group, said: “If based on these results, we can confirm a link between infertility and this gene, this could lead to a path for the early detection and treatment based on the genetic diagnosis of the infertility.”