BRD2 and obesity due to melanocortin 4 receptor deficiency: Currently, the pathogenesis of PCOS is not yet completely understood and is still under continuous research, but a number of studies have suggested that HPO axis dysfunction, elevated androgen, IR/hyperinsulinemia, elevated LH/FSH ratio, obesity, oxidative stress, and impaired negative feedback regulation of steroid hormones can all promote the occurrence and development of PCOS (11, 21, 23–25).