P450 oxidoreductase deficiency: a new disorder of steroidogenesis affecting all microsomal P450 enzymes.

Abstract

Combined partial deficiency of 17alpha-hydroxylase and 21-hydroxylase activities was first described in 1985; however the genes for P450c17 and P450c21 in these patients lack mutations. In 1986 we postulated that this disorder might be due to mutations in P450 oxidoreductase (POR), the flavoprotein that donates electron to these and all other microsomal P450 enzymes, but this hypothesis was not tested until the POR gene sequence became available through the genome database. We found five POR missense mutations in our first four patients. In vitro assays of the activities of these mutations showed that the standard assay of POR activity, reduction of cytochrome c, correlated poorly with the patients' phenotypes, but that assays of POR-supported 17alpha-hydroxylase and 17,20 lyase activities correlated well. POR deficiency is a new disorder of adrenal and gonadal steroidogenesis that affects all microsomal cytochrome P450 enzymes, hence may have important implications for genetic differences in drug metabolism.

• Authors: Amit V Pandey, Christa E Flück, Ningwu Huang, Toshihiro Tajima, Kenji Fujieda, Walter L Miller
• Journal: Endocrine research (Endocr Res) Vol. 30 Issue 4 Pg. 881-8 (Nov 2004) ISSN: 0743-5800 [Print] England
• PMID: 15666840 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Steroids
• Cytochrome P-450 Enzyme System
• NADPH-Ferrihemoprotein Reductase

Topics

• Abnormalities, Multiple (genetics)
• Alleles
• Bone and Bones (abnormalities)
• Craniosynostoses (genetics)
• Cytochrome P-450 Enzyme System (metabolism)
• Humans
• Microsomes (enzymology)
• Mutation
• NADPH-Ferrihemoprotein Reductase (deficiency, genetics)
• Steroids (biosynthesis)
• Syndrome