FSHB and polycystic ovary syndrome: A notable example is SNPs upstream of the transcription start site of FSHB. SNPs in this region are associated with increased concentrations of circulating FSH,88 decreased concentrations of LH,88 shorter menstrual cycles,89 increased dizygotic twinning,54 decreased risk of PCOS,69 increased endometriosis risk,95 and earlier menopause96 (Fig. 4).