The underlying mechanisms proposed are that some women with PCOS show neuro-endocrine abnormalities; moreover, the supraphysiologic estradiol (E2) level cause apparent increase in the number of follicles and insufficient number of LH receptor (14), therefore, a single dose of GnRHa might not lead to LH surge over a threshold level in these participants. Here, PLOD1 is linked to polycystic ovary syndrome.