Study identifies new variants for polycystic ovary syndrome

Scientists from the Institute of Genomics of the University of Tartu recently identified the association between polycystic ovary syndrome and genetics. The study was published in the Human Reproduction journal.

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Polycystic ovary syndrome, a common endocrine disorder in women, is characterized by irregular periods, increased levels of androgen hormones, and/or enlarged ovaries with numerous follicles containing the eggs (called polycystic ovaries). These affect fertility along with posing risk for other metabolic disorders.

It is a multifactorial condition, meaning both genetics and environmental or lifestyle factors increase the risk.”

Triin Laisk, Associate Professor, Institute of Genomics, University of Tartu

To identify variants in polycystic ovary syndrome genome-wide association researches can be carried out.

This technique compares the genetic material (DNA) sequence in women with polycystic ovary syndrome, for instance, to women without the condition and allows the identification of sequence changes which are more frequent in the group with the trait of interest.”

Triin Laisk, Associate Professor, Institute of Genomics, University of Tartu

Earlier researchers employed a similar approach by including many women from various European populations, pinpointing genes involved in DNA repair, maturation of the ovarian follicles that have the oocytes, cell growth and division, and synthesis of androgen hormones, among others associated with polycystic ovary syndrome.

The current study too used the same approach however it included Estonian and Finnish populations. Two new rare genetic variants that intensify the risk for polycystic ovary syndrome are elaborated, which likely impacts the gene CHEK2.

Due to differences in demographic history, the enrichment of some variants in Finnish and Estonian populations provided a unique opportunity to capture novel rare genetic variants associated with polycystic ovary syndrome when focusing only on these populations.”

Natàlia Pujol Gualdo, Study Co-First Author and PhD Student, University of Tartu

CHEK2 codes for a protein that is a vital factor in the quality control of cells and DNA repair. CHEK2 is also associated with ovarian reserve and variations in age at menopause. This is in line with the observed later age at menopause in women with polycystic ovary syndrome.

Laisk also adds, “Further research is needed to explore the role of CHEK2 variation in polycystic ovary syndrome and we hope this study serves as a base for further experiments that can clarify their interplay. At the same time, this study highlights the importance of population-specific biobank initiatives as unique means to seek into the genetic landscape of complex diseases.”

The research co-headed by co-workers from the University of Oulu forms a basis for collaboration to analyze the genetic underpinnings of various female reproductive conditions. The study used unique information from Estonian and Finnish populations.

With the help of the biobank participants, the researchers were able to examine genetic data of more than 233,000 women from the Estonian Biobank and the FinnGen study coordinated by the University of Helsinki—which facilitated the discovery of the new genetic risk factors in polycystic ovary syndrome.