Discovered, the gene that predicts when women will start menopause
A gene which staves off the menopause has been identified, raising hopes of a treatment to extend fertility and a means of identifying which women are safer to delay motherhood.
Scientists from the universities of Cambridge, Exeter and Copenhagen studied the genomes of hundreds of thousands of women and discovered 300 gene variants that influence their reproductive lifespan.
Many were found to be linked to DNA repair, including two genes called CHEK1 and CHEK2.
Women who naturally lack an active CHEK2 gene were found to reach menopause around 3.5 years later than those with an active gene.
When the researchers knocked out the same gene in mice, and instead ramped up the CHEK1 gene, the animals were fertile for 25 per cent longer.
Dr John Perry, of the medical research council epidemiology unit at the University of Cambridge, and a senior author on the paper, said: “This research is incredibly exciting.
“Although there’s still a long way to go, by combining genetic analysis in humans with studies in mice, plus examining when these genes are switched on in human eggs, we now know a lot more about human reproductive ageing.
“It also gives us insights into how to help avoid some health problems that are linked to the timing of menopause.”
Unlike men, who are constantly producing new sperm, women are born with a limited supply of eggs, which degrade over time. When they run out, a woman goes through the menopause, usually around the age of 50.
Scientists said that it appeared that some women had genes that were better at repairing damage to eggs and so were fertile for longer.
Prof Eva Hoffmann, of the University of Copenhagen, said: “It is clear that repairing damaged DNA in eggs is very important for establishing the pool of eggs women are born with and also for how quickly they are lost throughout life.
“Improved understanding of the biological processes involved in reproductive ageing could lead to improvements in fertility treatment options.”
The team also examined the health impacts of having an earlier or later menopause by using an approach that tests the effect of naturally occurring genetic differences. They found that a earlier menopause increased the risk of type 2 diabetes and was linked to poorer bone health and increased risk of fractures.
However, it decreased the risk of some types of cancer, such as ovarian and breast cancer.
Dr Katherine Ruth, of the University of Exeter, said: “By finding many more of the genetic causes of variability in the timing of menopause, we have shown that we can start to predict which women might have earlier menopause and therefore struggle to get pregnant naturally.
“And because we are born with our genetic variations, we could offer this advice to young women.”
The research was published in the journal Nature.
