Aromatase, or Cytochrome P450 family 19 subfamily A member 1, is a human gene encoded by CYP19A1. It may also be known as: Aromatase; CYPXIX; Cytochrome P-450AROM; Cytochrome P450 19A1; Estrogen synthase ; ARO; ARO1; CPV1; CYAR; CYP19; P-450AROM; cytochrome P450, family 19, subfamily A, polypeptide 1. The encoded protein is an enzyme with an amino acid length of 503 and a mass of 57.9 kDa. Other isoforms may exist. Homologs of this gene exist in other organisms, including: Rat, Frog.