Ambiguous genitalia due to partial activity of cytochromes P450c17 and P450c21

Arie Augarten, Clara Pariente, Ephraim Gazit, Rafael Chayen, Haya Goldfarb, Joseph Sack

Research output: Contribution to journalArticlepeer-review


We describe a patient with male pseudohermaphrodism who has normal basal serum concentrations of cortisol and high basal levels of progesterone and 17 hydroxyprogesterone. Serum concentrations of androstendione, dehydroepiandrosterone sulfate and testosterone were low. On adequate human chorionic gonodotropin (HCG) stimulation, no rise in serum androstendione, dehydroepiandrosterone sulfate or testosterone concentrations was observed. After ACTH stimulation there was an excessive rise in progesterone and 17 hydroxyprogesterone with no rise in androstendione, dehydroepiandrosterone sulfate, testosterone, deoxycorticosterone or cortisol. These clinical and laboratory data suggest that the patient has a combined defect in both cytochromes P450c17 and P450c21. The genes coding for these cytochromes are on different chromosomes, 10 and 6, respectively. Unlike isolated 21 hydroxylase deficiency where all identical HLA siblings suffer from the disease, HLA typing of the patient's family revealed a healthy brother with identical HLA. This suggests that the gene coding for P450c21 on chromosome 6 is not affected and that the lesion might be on a common enzyme which donates an electron to both cytochromes, most probably a flavoprotein.

Original languageEnglish
Pages (from-to)37-41
Number of pages5
JournalJournal of Steroid Biochemistry and Molecular Biology
Issue number1
StatePublished - Jan 1992
Externally publishedYes


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