PCOS: polycystic ovary syndrome; BMI: body mass index; FSH: follicle-stimulating hormone; LH: luteinizing hormone; AMH: anti-müllerian hormone; AFC: antral follicle count; MII: metaphase II; MI: metaphase I; GV: germinal vesicle. The gene discussed is BRD2; the disease is polycystic ovary syndrome.