[Hirsutism in Chilean women: importance of 21-hydroxylase congenital deficiency of late onset].

The prevalence of steroid 21-hydroxylase (21-OHase) deficiency of late onset was investigated in a Chilean population of hirsute women. In 33 hirsute patients, not family related, plasma 17-alpha hydroxyprogesterone (170H-P) was measured under basal conditions and after ACTH stimulation. Three cases of complete deficiency of late onset or post menarche type were found, a prevalence of 91% similar to that reported by others. Affected patients were indistinguishable from other hirsute women, except in 170H-P concentrations after ACTH. Plasma testosterone and dihydroepiandrosterone sulphate were significantly higher in hirsute women, either deficient of without enzyme deficiency, compared with a control group of 19 normal women. The 170H-P post ACTH levels of hirsute women who did not comply with criteria for enzyme deficiency were similar to control's. However, in these patients there was a significant correlation between hirsutism and 170H-P post ACTH, suggesting the presence of patients with mild enzyme deficiency, perhaps heterozygous for the defective gene. In conclusion, measurement of basal and post ACTH 170H-P during diagnostic work up in hirsute patients allows the detection of a significant number of cases with enzyme deficiency.