Homozygous mutation G539R in the gene for P450 oxidoreductase in a family previously diagnosed as having 17,20-lyase deficiency

Eli Hershkovitz, Ruthi Parvari, Stefan A. Wudy, Michaela F. Hartmann, Larissa G. Gomes, Neta Loewental, Walter L. Miller

    Research output: Contribution to journalArticlepeer-review

    78 Scopus citations

    Abstract

    Context: Very few patients have been described with isolated 17,20-lyase deficiency who have had their mutations in P450c17 (17α-hydroxylase/17,20- lyase) proven by DNA sequencing and in vitro characterization of the mutations. Most patients with 17,20-lyase deficiency have mutations in the domain of P450c17 that interact with the electron-donating redox partner, P450 oxidoreductase (POR). Objective: Our objective was to clarify the genetic and functional basis of isolated 17,20-lyase deficiency in familial cases who were previously reported as having 17,20-lyase deficiency. Patients: Four undervirilized males of an extended Bedouin family were investigated. One of these has previously been reported to carry mutations in the CYP17A1 gene encoding P450c17 causing isolated 17,20-lyase deficiency. Methods: Serum hormones were evaluated before and after stimulation with ACTH. Urinary steroid metabolites were profiled by gas chromatography-mass spectrometry. Exons 1 and 8 of CYP17A1 previously reported to harbor mutations in one of these patients and all 15 coding exons of POR were sequenced. Results: Gas chromatography-mass spectrometry (GC-MS) urinary steroid profiling and serum steroid measurements showed combined deficiencies of 17,20-lyase and 21-hydroxylase. Sequencing of exons 1 and 8 of CYP17A1 in two different laboratories showed no mutations. Sequencing of POR showed that all four patients were homozygous for G539R, a previously studied mutation that retains 46% of normal capacity to support the 17α-hydroxylase activity but only 8% of the 17,20-lyase activity of P450c17. Conclusion: POR deficiency can masquerade clinically as isolated 17,20-lyase deficiency.

    Original languageEnglish
    Pages (from-to)3584-3588
    Number of pages5
    JournalJournal of Clinical Endocrinology and Metabolism
    Volume93
    Issue number9
    DOIs
    StatePublished - 1 Jan 2008

    ASJC Scopus subject areas

    • Endocrinology, Diabetes and Metabolism
    • Biochemistry
    • Endocrinology
    • Clinical Biochemistry
    • Biochemistry, medical

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