Ma W, Li S, Liu H, et al. - In view of the inter-individual variability in enzyme activities induced by genetic variations in myeloperoxidase (MPO; G‐463A) and NADPH oxidase p22phox subunit (CYBA; C242T), researchers conducted this case‐control study to explore the connections between MPO activity and the MPO G‐463A and CYBA C242T polymorphisms in Chinese women with polycystic ovary syndrome (PCOS). Participants in the study were 1,003 patients with PCOS and 810 controls. In the PCOS group, the frequencies of the GA + AA genotype and A allele frequency of the MPO G‐463A polymorphism were significantly higher than in the control group. The MPO G‐463A variant is associated with a risk of PCOS in Chinese women, but not with the CYBA C242T variant.