Abnormal enzyme concentration or activity Abnormal aromatase activity 2023-04-15T11:23:04Z Aromatase activity outside of the normal range. Aromatase is a specific component of the cytochrome P450 enzyme system responsible for the transformation of androgen precursors into estrogens. This enzyme is encoded by the CYP19A1 gene located at chromosome 15q21.2, that is, expressed in ovary and testis, but also in many extraglandular sites such as the placenta, brain, adipose tissue, and bone.