Steroid 17-alpha-hydroxylase/17,20 lyase (CYP17A1) is involved in the conversion of pregnenolone and progesterone to their 17-alpha-hydroxylated products and subsequently to dehydroepiandrosterone (DHEA) and androstenedione. It catalyses both the 17-alpha-hydroxylation and the 17,20-lyase reaction and is involved in sexual development during fetal life and at puberty [].Mutations in the CYP17A1 gene cause adrenal hyperplasia 5 (AH5), a form of congenital adrenal hyperplasia, a common recessive disease due to defective synthesis of cortisol [, ].
