PLOD1 and ovarian dysfunction: The study by Blumenfeld et al. defined POI as hypergonadotropin amenorrhea (menopause > 6 months, FSH > 40 U/L), while ovarian failure after transplantation was defined by Cheng and coworkers as the continuation of menstruation cessation for > 3 months in a patient who was premenopausal at the beginning of the study with the following hormonal parameters: (a) serum FSH level > 20 IU/L, (b) serum LH level > 20 IU/L, and (c) serum estradiol level > 30 pmol/L.