Comparison of two tests for heterozygosity in congenital adrenal hyperplasia (CAH).
The increase of plasma cortisol (F), androstenedione (A), 17 alpha-hydroxy-progesterone (17-OH-P) and testosterone (T) was measured after iv administration of ACTH in heterozygotes for CAH and in controls under two different conditions: Test 1: ACTH stimulation was performed without any particular preparation. Test 2: 1.5 mg of dexamethasone (dex.) was given the evening before the ACTH stimulation. Plasma F, A, 17-OH-P and T were measured by specific radioimmunoassays (RIA). Following ACTH stimulation, the increase of 17-OH-P was significantly higher in CAH-heterozygotes than in controls in both tests (P less than 0.0005). Heterozygotes were characterized by a 17-OH-P increase after ACTH stimulation exceeding the + 2 SD limit of the 17-OH-P increase found in controls. The detection of female heterozygotes was considerably improved by the administration of dex. before testing (test 2). In males, however, a better identification of heterozygotes was obtained without previous administration of dex. (test 1). By these tests, 100% of female (test 2) and 79% of male (test 1) CAH heterozygotes could be correctly identified. There were no significant differences in the levels of F, A and T between heterozygotes and controls except for decreased T levels in test 1 (2P less than 0.01) in most male heterozygotes after ACTH stimulation.
D000304:Adrenal Cortex Function Tests / Q000379:methods*; D000312:Adrenal Hyperplasia, Congenital; D000308:Adrenocortical Hyperfunction / Q000097:blood / Q000235:genetics; D000324:Adrenocorticotropic Hormone; D000735:Androstenedione / Q000097:blood; D003907:Dexamethasone; D005069:Evaluation Studies as Topic; D005260:Female; D006579:Heterozygote; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D006908:Hydroxyprogesterones / Q000097:blood; D008297:Male; D010912:Pituitary-Adrenal Function Tests / Q000379:methods*; D013739:Testosterone / Q000097:blood
D006908:Hydroxyprogesterones; D013739:Testosterone; D000735:Androstenedione; D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone