Whole-exome sequencing and functional validation reveal a rare missense variant in MMP7 that confers ovarian endometriosis risk

Prior studies have shown that genetic factors play important roles in ovarian endometriosis. Herein, we first analyzed the whole-exome sequencing data from 158 patients with ovarian endometriosis and 385 local control women without endometriosis. Among which, a rare missense variant in the MMP7 (p.I79T, rs150338402) gene exhibited a significant frequency difference. This rare variant was screened in an additional 1176 patients and 600 control women via direct DNA sequencing. Meanwhile, a total of 38 available clinical characteristics were collected. Our results showed 45 out of 1334 (3.37%) patients, while 15 out of 985 control women (1.52%) (P = 0.0076) harbored this rare variant, respectively. This rare variant was associated with clinical features such as follicle-stimulating hormone (P-adj = 0.0342), luteinizing hormone (P-adj = 0.0038), progesterone (P-adj = 1.4e-7), testosterone (P-adj = 0.0923), total bilirubin (P-adj = 0.0699), carcinoembryonic antigen (P-adj = 0.0665) and squamous cell carcinoma antigen (P-adj = 0.0817), respectively. Functional assays showed that this rare variant could promote cell migration, invasion, epithelial-mesenchymal transition (EMT) and increase the proteolytic protein activity of MMP7, implicating that the increased capacities of cell invasion, migration and EMT might be mediated by enhanced proteolytic activity of MMP7 mutant. These results showed that the MMP7 rare missense variant (p.I79T) played important roles in the pathogenesis of ovarian endometriosis. In conclusion, we identified, for the first time, a significantly enriched MMP7 rare variant in ovarian endometriosis; this rare variant was closely associated with certain clinical features in ovarian endometriosis; thus, it could be a promising early diagnostic biomarker for this disease.