New research by scientists at the University of Cambridge and ten other institutions, including 23andMe, has uncovered half-a-dozen genetic variants associated with polycystic ovary syndrome, the most common reproductive disorder in women and a common cause of infertility.
Published this week in the journal Nature Communications, this is the largest genome wide association study to date on the condition involving genetic information from more than 200,000 women.
Researchers believe the insights from this study could help drive treatment and care for women.
“Not only did we find new genetic markers for polycystic ovary syndrome, but the findings also help us understand the biology of the disease,” said Dr John Perry, of the Medical Research Council (MRC) Epidemiology Unit at the University of Cambridge, and one of the lead authors of the study.
The researchers found that the risk of polycystic ovary syndrome increased because of genetic variants that were also associated with higher body mass index and insulin resistance. Therapies that lower body mass index and insulin resistance may help women with the condition, the researchers suggest.
“Previous studies had suggested that weight loss has only partial benefits,” said Dr Ken Ong, of the MRC Epidemiology Unit and another lead author. “We recommend that new studies should be done to test whether more intensive efforts to reduce body weight and improve insulin resistance are effective in treating women with (polycystic ovary syndrome).”
In addition to these associations, the study also identified new genetic variants that implicate three of the four epidermal growth factor receptor genes (ERBB4/HER4), which are known targets of some modern cancer therapies. This suggests new avenues for research into future treatments for polycystic ovary syndrome.
On top of these genetic variants researchers also identified a new variant in the FSHB gene associated with polycystic ovary syndrome. The FSHB gene encodes the ‘follicle stimulating hormone,’ and low levels of this hormone may contribute to the development of syndrome.
One of the paradoxes of the condition is why it is so prevalent, which is counter-intuitive. A condition that reduces fertility would seem to over time become less and less prevalent. But researchers believe that it might mean that polycystic ovary syndrome is associated with a beneficial trait, such as a longer fertility span.
The condition is very common. Estimates are that in the UK alone it affects one in every five women. It is a leading cause of fertility problems and is also associated with an
increased risk of developing health problems in later life, such as type 2 diabetes and high cholesterol.
For this study, the researchers used genetic information from more than 5,000 women of European ancestry who are 23andMe customers, reported having PCOS and consented to research. The study also included another 82,000 women customers of 23andMe who also consented to research but do not have the condition. Those women were used as controls for the study.
To help validated the findings the researchers also followed-up the study looking at 2,000 other women, whose PCOS had been clinically validated, and then looked at another 100,000 women without the condition. Those women were studied by the Icelandic company deCODE, by researchers at the Erasmus Medical Center in the Netherlands, and also at the Center for Human Genetic Research at Massachusetts General Hospital in Boston, USA.