Objective: Dysregulation of 17 alpha-hydroxylase (CYP17) has been proposed as a cause of hyperandrogenism. We have determined the prevalence of a polymorphic allele in the CYP17 gene in sporadic patients with polycystic ovaries (PCOS) compared to a reference population, and to a group of hyperandrogenic individuals, to assess its significance to androgen production.
Patients and design: DNA was isolated from EDTA blood samples from 69 patients with PCOS, 63 patients with congenital adrenal hyperplasia secondary to 21-hydroxylase deficiency and 124 consecutive patients attending for a full blood examination. The thymine (T) to cytosine (C) polymorphism at -34 base pairs (bp), denoted alleles A1 and A2 respectively, was detected by amplification of DNA followed by restriction enzyme digestion.
Measurements: Testosterone and LH. The frequency of alleles A1 and A2 in each of the subject groups was determined.
Results: The prevalences of the A1 and A2 alleles were 75 and 25% respectively in the PCOS group which was not significantly different from that in either the hyperandrogenic or the reference group. Neither allele segregated with hyperandrogenism.
Conclusion: The polymorphism plays no apparent role in the dysregulation of CYP17.