New Genetic Variants Associated with Endometriosis May Offer New Opportunities

Novel Loci Associated with Endometriosis

Key Points

Highlight

• Scientists identified novel genetic variants associated with endometriosis that is in or near genes with distinct roles in sex steroid hormone signaling and function.

Importance

• Identification of specific gene variants permits targeted functional research into future diagnostic or therapeutic.   

What's done here

• Meta-analysis of eleven genome-wide association studies consisting of 17,045 endometriosis cases and 191,596 controls data set.

Data

• Five loci implicating genes in sex steroid hormone pathways have been shown to associate with endometriosis risk significantly.
• These loci included FN1, CCDC170, Estrogen Receptor 1 (ESR1), and FSHB, some of which are essential genes that are involved in hormone metabolism and may play a significant role in endometriosis pathogenesis.
• In total, there were 19 independent single nucleotide polymorphisms robustly associated with endometriosis.

Limitations:

• Array-based genotyping instead of whole genome sequencing may be less comprehensive.

Lay Summary

Endometriosis is a heritable gynecological condition. Its etiology and pathogenesis remain complex with multiple genetic and environmental risk factors. Previous studies based on female twins and common SNPs have suggested the heritability of endometriosis.

In the May 2017 issue of Nature Communication, Sapkota et al. reported genome-wide association studies to gain a better understanding of the genetic background of endometriosis. This meta-analysis studies combined genome-wide association data from eleven individual case–control datasets, covering around 7 million SNPs. The total number of endometriosis cases were 17,045 and 191,858 controls from Australia, Iceland, Belgium, UK, USA, Denmark, and Japan. Individuals in the study were predominantly Europeans (93%), and the remaining Japanese descent.

The results confirmed 9 out of 11 previously reported risk loci. Also, the authors also identified five new genomic regions in or near FN1, CCDC170, ESR1 and FSHB harboring endometriosis risk loci. A total of 19 known and newly identified SNPs robustly associated with endometriosis and explained up to 5.19% of the variance in endometriosis. Most importantly, these results showed key genes that are involved in hormone metabolism and may play a significant role in endometriosis pathogenesis. For example, variants in the region that include Estrogen Receptor 1 (ESR1) on chromosome 6p25.1, is in line with our understanding that endometriosis is an oestrogen-dependent disease. SNPs located in the region of FSHB suggested roles of FSH and LH gonadotropin hormones, which are known to regulate ovarian follicle development and influencing oestradiol release.

In summary, these genome-wide association studies provide a robust analysis of genetic variation in endometriosis, covering large sample size in comparison to the previously multi-ethnic studies. One limitation includes the use of genotyping arrays which may be less comprehensive than whole genome sequencing. The analyses provide evidence for new variants and offer opportunities for future more targeted research efforts.

Research Source: https://www.ncbi.nlm.nih.gov/pubmed/28537267