Mitochondrial DNA 4977 bp Deletion in Peripheral Blood Is Associated With Polycystic Ovary Syndrome

BACKGROUND: Polycystic ovary syndrome (PCOS) is a common endocrine disorder worldwide. We aimed to examine the associations of two mitochondrial DNA (mtDNA) biomarkers in the peripheral blood, mtDNA copy number (CN), and mtDNA(4977) deletion rate (DR), with PCOS in a clinical setting. METHODS: We performed a study involving 263 women with PCOS and 326 age-matched controls between June 2015 and June 2019. The mtDNA CN and mtDNA(4977) DR were measured using multiplex probe-based qPCR. The associations of the mtDNA CN and mtDNA(4977) DR with the risk of PCOS were estimated using logistic regression. RESULTS: Analysis of the associations between mtDNA biomarkers and PCOS indicate that the mtDNA CN (P = 0.003) and mtDNA(4977) DR (P < 0.001) in PCOS patients were significantly higher than those in the controls. After adjusting for the body mass index, luteinizing hormone/follicle-stimulating hormone ratio, and testosterone level, only higher mtDNA(4977) DR was associated with PCOS (odds ratio 1.053, 95% confidence interval 1.024 to 1.083; P < 0.001). The linear dose-response trends of the mtDNA(4977) DR were also supported by the quartile analysis. CONCLUSION: Multivariable models suggest that mtDNA(4977) DR levels are strongly associated with PCOS and represent an independent risk factor for PCOS. Further investigation of the utility of mtDNA as a biomarker for PCOS is warranted.