Scientists pinpoint genetic variants linked with endometriosis
An international team of scientists has identified two genetic variants that raise the risk of developing endometriosis, a common gynaecological condition. The findings, published in the journal Nature Genetics, could lead to new and improved ways of diagnosing and treating the disease. Endometriosis is estimated to affect some 170 million women globally, or up to 10% of women of reproductive age. It occurs when cells similar to those which line the womb start to grow and accumulate on other organs in the pelvis, such as the ovaries and bowel. Symptoms include chronic pelvic pain, painful periods and, in some cases, infertility. The only way of obtaining a reliable diagnosis involves looking into the pelvis with a laparoscope, so many patients remain undiagnosed for many years. Treatments include surgery and hormonal drugs that come with many side effects. 'Endometriosis can be a painful and distressing condition that affects a significant number of women in their reproductive years,' said Dr Krina Zondervan of the University of Oxford in the UK. 'We've known for some time that endometriosis is heritable, but until now we have been unable to find any robust genetic variants that influence a woman's risk of developing the disease.' 'We have conducted the largest genome-wide association study to date - the first in women of European ancestry - comparing the DNA [deoxyribonucleic acid] of 5,586 women with endometriosis and 9,331 people without,' explained Professor Grant Montgomery of the Queensland Institute of Medical Research in Australia. The team identified two regions of the genome associated with an increased risk of endometriosis. The first and strongest lies on chromosome 7; this region may be involved in the regulation of nearby genes involved in the development of the womb and its lining. The team also confirmed that a genetic variant on chromosome 1 is associated with endometriosis. This second variant lies near the gene WNT4, which is involved in hormone metabolism and the development and function of the female reproductive tract. 'Our study is a breakthrough because it provides the first strong evidence that variations in DNA make some women more likely to develop endometriosis,' stated Dr Zondervan. 'We now need to understand the effect of these variations on cells and molecules in the body.' The genetic contribution appears to be particularly strong for more severe forms of the condition. 'Previous studies have established that endometriosis is heritable, but have not examined the impact of genetics for different disease stages,' commented Professor Montgomery. 'Our study demonstrates a stronger genetic contribution to moderate-to-severe endometriosis, which has implications for how we research the condition in the future.' The University of Oxford's Dr Stephen Kennedy concluded: 'We have great confidence that the results of this study will help towards developing less invasive methods of diagnosis and more effective treatments for endometriosis.' The work was carried out by the International Endogene Consortium, which brings together researchers at the University of Oxford (the Nuffield Department of Obstetrics and Gynaecology plus the Wellcome Trust Centre for Human Genetics) and the Queensland Institute of Medical Research, as well as Harvard Medical School and Brigham and Women's Hospital in the US.
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Australia, United Kingdom, United States