Polycystic ovary syndrome may be passed on via chemical tags on DNA

Polycystic ovary syndrome can be transmitted by families via chemical labels that modify the structure of DNA, which suggests that the drugs that modify these labels in embryos could prevent the condition.

People with polycystic ovary syndrome (SOPK) have at least two of the three key characteristics: high levels of male sex hormones such as testosterone, irregular periods or none at all, and an accumulation of immature eggs – which appear as cysts – on their ovaries.

The condition often works in families, but it is not clear exactly how it is inherited. “About 25 to 30 [genetic mutations] Were linked to the SOPK, but this explains only a small fraction of the inheritance, “explains Elisabet Stener-Victorin at the Karolinska Institute in Sweden.

Studies on mice suggest that changes in epigenetic marks – chemical labels that activate and deactivate genes without modification of DNA sequences – can also play a role. It is believed that most of these brands are erased when eggs are formed, but some are supposed to remain, a potential form of inheritance.

To see if this happens in relation to the SOPK in humans, Qaianshu Zhu at the Chongqing Medical University in China and his colleagues analyzed the epigenetic brands in eggs and embryos aged 3 days given by 133 people with SOPK and 95 without condition. “No one really did this in this way in human material,” explains Stener-Victorin.

This revealed a link between being a donor with the SOPK and the changes in the models of three types of epigenetic brands in eggs and embryos. Two of these marks turn off the genes by making the DNA coil more closely around proteins called histones, which help to wrap it in the cells. This makes the genetic code in DNA less accessible to molecules which transcribe it into RNA, a key step in the manufacture of proteins. The third type of brand activates genes by loosening DNA coils.

Together, the epigenetic changes linked to the SOPK have changed the metabolism of eggs and embryos, which suggests that they can increase the risk of sopk in offspring. But other studies should explore how they affect the symptoms of SOPK in the offspring of mice and humans, explains Stener-Victorin. “For the moment, we simply know that these marks are different; This does not necessarily mean that they have a negative effect, ”she says.

In another experience, the team used a drug to reverse epigenetic changes, which suggests that this could reduce the risk of sopk. “If we confirm that the modification of these brands of histone changes the sopk features in the next generation, we will have a powerful target for prevention,” Zhu said in a press release. In addition, the team says that clinicians could potentially use SOPK -related epigenetic brands to select the healthiest embryos during in vitro fertilization.

ZHU presents the results in the annual meeting of the European Society for Human Reproduction and Embryology in Paris on July 1.