Clinical and biological phenotypes in late-onset 21-hydroxylase deficiency.

We analyzed data from 20 patients with late-onset 21-hydroxylase deficiency (LOHD). Three clinical phenotypes could be distinguished among the 18 women. Seven (39%) presented with clinical features suggesting polycystic ovarian disease (PCOD). However, despite androgen levels similar to those of patients with typical PCOD, high serum LH to FSH ratios were not consistently found. Seven other women (39%) presented with isolated hirsutism, suggesting idiopathic hirsutism. The remaining 4 women (22%) had no manifestations of androgen excess and were considered to have the cryptic form of LOHD. Serum 17-hydroxyprogesterone (17-OHP) and androgen levels were similar in the 3 phenotypes, suggesting that the clinical expression of LOHD in women is modulated by individual factors, such as androgen sensitivity. The 2 men were detected by family study and were clinically normal. Since clinical diagnosis of LOHD is impossible, we concentrated on hormonal data with the aim of providing guidelines for the biological diagnosis of LOHD. Assay of basal serum 17-OHD at 0800 h in both sexes and in the early follicular phase in women was sufficient to establish the diagnosis of LOHD in most patients. If doubtful results are obtained, i.e. serum 17-OHP levels between 2 and 5 ng/ml, an ACTH test must be performed. Post-ACTH serum 17-OHP levels exceeding 10 ng/ml confirm the diagnosis of LOHD. Such results should avoid confusion with heterozygotes for 21-hydroxylase deficiency, whose frequency is high within the general population and may be even higher in patients with idiopathic hirsutism or PCOD.