Chinese scientists say they have found a key cause of female infertility
Researchers from the People's Republic of China have discovered a mutation that causes premature ovarian failure. According to them, it may be the main cause of female infertility.
Infertility is a disease of the male or female reproductive system, defined as the absence of pregnancy for a year or more despite regular unprotected sexual activity. This pathology affects approximately 48 million couples worldwide. Up to 3.7% of women suffer infertility due to premature ovarian insufficiency (PCOS), which is a decrease in follicle reserves and synthesis of sex hormones that occurs in women under 40 years of age.
Statistically, 30% of cases of PNF are due to various genetic causes. One of them is related to changes in the Eif4enif1 gene.
Scientists from Tsinghua University in China decided to reproduce the mutation in mice to understand how it affects infertility in women. The results were published in the journal Development.
The rodents were altered using gene editing technology, or CRISPR "genetic scissors". The scientists then compared their fertility with that of mice whose DNA had not been edited. During the experiments, it turned out that mutations in the Eif4enif1 gene affected the eggs because the mitochondria malfunctioned.
The scientists found that the average number of follicles (the structural unit of the ovary consisting of an egg in its embryonic state) that contain oocytes decreased by about 40% in old and genetically modified mice. The average number of mice in each litter decreased by 33%.
The researchers also examined the oocytes under a microscope. They noticed that mitochondria, which are normally evenly distributed throughout the egg, appeared clustered. Previously, no connection between the Eif4enif1 gene and mitochondria had been noticed by scientists. According to the authors of the new scientific work, if people with infertility have the same defects, the restoration of the correct behavior of mitochondria should improve fertility.
Previously, Chinese scientists reported that women living in more air quality-impaired areas had a 20% higher risk of infertility compared to those living in relatively favorable environments.