Premature Ovarian Insufficiency (POI) is defined as the loss of normal ovarian function before the age of 40, characterized by amenorrhea or oligomenorrhea for at least four months and elevated gonadotropin levels (FSH > 25 IU/L on two separate occasions ≥ four weeks apart), with or without low estradiol levels. The gene discussed is BRD2; the disease is Oligomenorrhea.