Abnormalities of 21-Hydroxylase Gene Ratio and Adrenal Steroidogenesis in Hyperandrogenic Women with an Exaggerated 17-Hydroxyprogesterone Response to Acute Adrenal Stimulation*

Abstract

One to 2% of hyperandrogenic women demonstrate a 17-hydroxyprogesterone (17-HP) level greater than 36.3 nmol/L (1200 ng/dL) after acute ACTH-(1-24) adrenal stimulation, consistent with 21-hydroxylase (21-OH) deficient late-onset adrenal hyperplasia (LOAH). The following study was undertaken to endocrinologically and genetically define hyperandrogenic patients with an exaggerated 17-HP response to ACTH stimulation, and which do not represent LOAH. Of 265 consecutive patients suffering from hirsutism and/or hyperandrogenic oligomenorrhea, 23 (8.7%) demonstrated a 17-HP level 30 min post stimulation greater than 9.6 nmol/L or 316 ng/dL (the upper 95th percentile in 41 eumenorrheic nonhirsute healthy control women). Seven patients or five separate families (1.8% of total) demonstrated poststimulation 17-HP levels consistent with LOAH. Of the remaining 16 patients, the net increment in 17-HP (delta 17-HP0-30) was within normal limits in seven (2.6%) and these women were assumed to have a normal 17-HP adrenocortical response superimposed on an elevated basal level of nonadrenal (e.g. ovarian) origin. In the remaining nine hyperandrogenic patients (3.4%) various abnormalities of adrenal response were noted in all but one patient, consistent with adrenal hyper-responsiveness. One patient demonstrated an 11-deoxycortisol poststimulation level greater than 3-fold the upper 95th percentile of normal, consistent with 11-hydroxylase LOAH and was excluded from further study. Six of these women were available for further genetic characterization, all Caucasian and unrelated. Three were heterozygotes for HLA-B14, three for B40, and one for B35 antigen, HLA-types associated with the inheritance of 21-OH deficiencies. Although, normally there are two 21-OH genes (a pseudogene and a functional gene) present in a 1:1 ratio, we have previously reported a high frequency of 21-OH gene ratio abnormalities in LOAH. All but one of our patients demonstrated an abnormal 21-OH gene ratio. In conclusion, 3.4% of our hyperandrogenic population demonstrated an exaggerated 17-HP increment after ACTH stimulation, not consistent with LOAH or increased extraadrenal 17-HP production. The increased prevalence of HLA alleles known to be linked to inherited defects of 21-OH function and the increased frequency in 21-OH gene ratio abnormalities suggest that a majority of these individuals may be carriers for these genetic disorders. However, the adrenocortical abnormalities noted were more consistent with a generalized hyperreactivity of the adrenal to ACTH stimulation, than a specific enzyme deficiency, implying that carrier status for 21-OH deficiency may be incidental to the hyperandrogenism.