Two of these variants identified affect the CHEK2 gene. CHEK2 is a gene known to play a key role in cell quality control and the repair of damaged DNA that has also been linked to ovarian reserve and differences at age of menopause (see BioNews 1107).
'This technique compares the genetic material (DNA) sequence in women with PCOS, 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,' said Dr Triin Laisk, associate professor at the Institute of Genomics at the University of Tartu in Estonia.
Conducted by researchers at University of Tartu and the University of Oulu in Finland, the study analysed the genetic data of over 233,000 women. A total of 3609 PCOS cases were identified from national registers with all other 229,788 women designated controls. First a genome wide association study was carried out using data on 141,355 women from the FinnGen study, and then these findings were validated using a separate dataset of 92,042 women from the Estonian biobank.
Published in the journal Human Reproduction, the findings included two causal variants in the CHEK2 gene and one on the MYO10X gene.
Previous research has discovered other genes associated with PCOS (see BioNews 997). The authors of this study believe however that using population-specific data could help provide further insights.
The Finnish population has a high number of genetic variants that occur at a low frequency across the rest of Europe, the authors note. The Estonian population is thought to be genetically closest to the Finnish population.
'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 PCOS when focusing only on these populations,' said Natàlia Pujol Gualdo, PhD student and co-first author of the study.
'Further research is needed to explore the role of CHEK2 variation in PCOS and we hope this study serves as a base for further experiments that can clarify their interplay,' said Dr Laisk. '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'.
It is not yet known whether these genetic variants will be found in other ethnic groups, but they contribute to our overall understanding of the genetic control of PCOS.