By Caitlin Tilley, Dailymail.Com Health Reporter
21:02 December 13, 2023, 21:07 Updated December 13, 2023
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Scientists have discovered a new underlying cause of female infertility.
Changes in a particular gene called Eif4enif1 have been identified as the cause of ovarian problems that make pregnancy nearly impossible.
Researchers at China’s Tsinghua University found that this apparent genetic change causes problems with egg cells, preventing the ovaries from releasing eggs regularly.
Without the release of an egg, the ovulation process, fertilization cannot occur.
Specifically, harmful patterns in DNA affect the function of mitochondria within egg cells, the “power plants” that convert fuel into energy.
Approximately 48 million couples around the world are affected by infertility, and approximately one in five women in the United States is infertile.
In about 1 to 2 percent of cases, the problem is caused by the ovaries’ inability to release eggs.
Professor Kehkooi Kee of Tsinghua University in China, who led the study, said the following about the research results. Eif4enif1 and mitochondria had not been previously identified.
Medically, problems with egg production and release are known as both primary ovarian insufficiency and premature ovarian insufficiency.
The term premature onset refers to the fact that the problem occurs before menopause, when ovulation naturally stops.
In 2019, researchers in China encountered a family with premature ovarian failure, all of whom had a change in the gene Eif4enif1.
The researchers replicated this genetic change in mice to see how it would affect human fertility.
They grew the mice and compared their fertility to mice whose DNA had not been edited.
They discovered a distinctive pattern of mitochondrial changes in eggs.
The average number of total follicles (small sacs on the surface of the ovary that contain developing eggs) was reduced by about 40 percent in older gene-edited mice.
The average number of baby rats per litter was also reduced by a third.
And when grown in a dish, about half of the fertilized eggs failed to survive beyond the early stages of development.
When researchers examined eggs from mice with low fertility under a microscope, they found that the mitochondria were not spread as evenly throughout the egg as they should be, but were clustered together.
Misbehaving mitochondria appear to be contributing to infertility in mice.
Researchers believe that restoring proper mitochondrial behavior may improve fertility.
Their next step is to see whether the mitochondrial defects are also found in the eggs of human patients.
The findings also suggest that gene-editing drugs have the potential to address this problem and provide effective treatments.
The study was published in the journal development.