CYP19A1 and polycystic ovary syndrome: Letrozole (LET), an aromatase inhibitor, has been recommended as a first-line therapy for anovulatory PCOS, which prevents the aromatase-induced conversion of androgens to estrogens, increases the secretion of follicle-stimulating hormone (FSH), and stimulates ovarian follicle development and maturation [4–6].