Cyp19a1, also known as aromatase, is a member of cytochrome P450 family of heme-thiolate monooxygenases. It converts androgens into estrogens, which is crucial for female sexual development as well as growth and development in both sexes. This process is part of the steroid biosynthesis pathway, and Cyp19a1 depends on reducing equivalents from the reduced nicotinamide adenine dinucleotide phosphate via the cytochrome P450 oxidoreductase coded by POR [3].

In a study of the Chinese Han population, the contribution of Cyp19a1 polymorphisms to coronary heart disease (CHD) susceptibility was found to be associated with age, gender, and clinical phenotypes (course of the disease and Gensini score) [1]. In a case-control study and meta-analysis in China, the Cyp19a1 rs700519 polymorphism was related to breast tumorigenesis, especially showing a significant negative relationship with risk and disease-free survival rates in postmenopausal hormone receptor-positive patients [2]. Also, in pregnant women using selective serotonin reuptake inhibitors (SSRIs), the enzyme activity of Cyp19a1 in placental microsomal fractions was lower compared to controls, which may lead to disturbances in maternal steroid hormone balance [4]. A study on endometriosis found that while there was no difference in Cyp19a1 mRNA expression in luteinized granulosa cells between women with stage III-IV endometriosis and controls, the correlation between Cyp19a1 expression and follicular estradiol levels, as well as the number of oocytes retrieved, was different between the two groups, highlighting a potential mechanism affecting ovulation in endometriosis patients [5].

In conclusion, Cyp19a1 is essential for estrogen synthesis and thus for sexual and general development. Studies on its polymorphisms and expression changes have revealed its associations with diseases such as coronary heart disease, breast cancer, and endometriosis, as well as its role in placental function during pregnancy. These findings contribute to our understanding of the biological functions of Cyp19a1 and its implications in various disease conditions.