An illustration of artificial insemination of a human egg cell Shutterstock/Maxx-StudioStudying the genes that control the age of menopause in women led to a new method of treating infertility.Infertility drugs are often used to induce multiple egg production during IVF treatment. When one gene is blocked in female mice, it causes the animals to respond more strongly to the infertility drugs.The average age at which menopause occurs is 50. However, infertility can occur several years before that time. There are many variables, and the eggs in the ovaries may play a role in how long it takes. The average number of eggs a girl is born with is around a million. By the time she reaches menopause, it has dropped to approximately a thousand. The number of eggs they have and their death rate affect the age at menopause.AdvertisementA large international group of researchers conducted the new study to examine genetic variants that can affect menopause age. It used records from 200,000 European women who had provided their DNA for sequencing, and completed health questionnaires such as those in the UK Biobank project.Researchers found that 290 DNA regions collectively account for about a third the genetic variation in menopause age. Lifestyle factors like smoking and drinking also play a role. Similar results were also found in records of nearly 80,000 East Asian women.Many genes found are linked to DNA repair processes. John Perry, from the University of Cambridge School of Clinical Medicine and a member of this research team, said that some genes are active before birth.CHEK2, a gene that is involved in programmed cell death, was found to have the greatest effect. The study showed that women with a defective variant of this gene go through menopause three years earlier than those with the working version.The team genetically altered female mice to eliminate CHEK2, and their eggs began to die off slower as they grew older. The mice also produced more eggs after they were given gonadotrophin (used during IVF to stimulate egg growth).Perry says that if we could create a drug that blocks CHEK2, this could allow IVF women to release more eggs. Perry says that CHEK2 causes viable eggs to become unviable. You could possibly get more eggs if you were to lower the CHEK2 level. However, you need to make sure that you aren't fertilizing eggs with damaged eggs.Perry said that the team is adding women to the genetic research and that the results could be used in the future to create a blood test for women who are at high risk of losing fertility or early menopause.These findings open the door to more detailed studies that could allow women to predict their menopause age and consider ways to prolong their reproductive life spans, Krina Zondervan from the University of Oxford stated in a commentary article alongside the paper.Journal references: Nature, DOI: 10.1038/s41586-021-03779-7; Zondervans commentary DOI: 10.1038/d41586-021-01710-8Subscribe to our Health Check newsletter to receive a weekly roundup of the latest health and fitness news, every Saturday
