This gene encodes a member of the cytochrome P450 superfamily of enzymes, which participate in drug metabolism and the synthesis of cholesterol, steroids and other lipids. This enzyme hydroxylates testosterone and dehydroepiandrosterone 3-sulphate, which is involved in the formation of estriol during pregnancy. This gene is part of a cluster of related genes on chromosome 7q21.1. Naturally-occurring readthrough transcription occurs between this gene and the downstream CYP3AP1 pseudogene and is represented by GeneID:100861540.Komori M., J. Biochem. 105:161-163(1989).Gellner K., Pharmacogenetics 11:111-121(2001).Scherer S.W., Science 300:767-772(2003).