Polycystic ovarian syndrome (PCOS) may be transmitted through families via chemical markers that modify DNA structure, implying that medications that adjust these markers in embryos could potentially prevent the disorder.

Individuals with PCOS usually display at least two of the following three key traits: elevated levels of male hormones like testosterone, irregular menstrual cycles, and the presence of immature eggs that resemble cysts in the ovaries.

While this condition frequently runs in families, its inheritance pattern remains unclear. “Around 25-30 genetic mutations are associated with PCOS, but they only account for a minor part of the hereditary aspects,” explains Elisabet Stener-Victorin from the Karolinska Institute in Sweden.

Research on mice indicates that variations in epigenetic marks (chemical tags that regulate gene activity without changing DNA sequences) may also be influential. As eggs develop, most of these marks are believed to be erased, but some may persist as a possible means of inheritance.

To investigate this in relation to human PCOS, Qianshu Zhu from China’s Chungin Medical University and colleagues conducted an analysis of the epigenetic markers in eggs and embryos donated 3 days prior, revealing data from 133 and 95 PCOS donors respectively. “No one has truly explored this with human samples,” states Stener-Victorin.

The study revealed a correlation between PCOS donation and altered patterns in three epigenetic marks in eggs and embryos. Two of these marks contribute to silencing genes and helping to package them within cells, resulting in a tighter DNA coil around a protein called histone, rendering the genetic code less accessible for RNA transcription, a crucial step in protein synthesis. Meanwhile, the third type of mark activates genes by loosening the DNA coil.

Together, the epigenetic modifications related to PCOS could potentially affect the metabolic processes of eggs and embryos, thereby elevating the chances of passing on PCOS to the next generation. Nevertheless, more research is essential to understand how these changes influence PCOS symptoms in offspring, both in mice and humans, as noted by Stener-Victorin. “At this stage, I recognize these marks differ, and that doesn’t inherently mean they are harmful,” she remarks.

Additional experiments suggest that the researchers may employ medications to reverse epigenetic alterations, potentially mitigating the risk of PCOS. “If we observe that modifying these histone marks changes the next-generation characteristics of PCOS, it could present a critical prevention target,” Zhu stated in a press release. Furthermore, the team posits that clinicians might utilize PCOS-related epigenetic markers to choose the healthiest embryos during in vitro fertilization procedures.

Zhu presented these findings at the European Breeding Association’s Annual Meeting held in Paris on July 1st.