An improved method for the detection of heterozygosity of congenital virilizing adrenal hyperplasia

A modified short ACTH test for the detection of heterozygote carriers of 21-hydroxylase deficiency (21-OHD) was applied to twenty-one controls and fourteen parents of children with 21-OHD. The following modifications were introduced: (1) Endogenous ACTH was suppressed by dexamethasone administration prior to the test, (2) Plasma 17-hydroxyprogesterone (17-OHP), cortisol (F), progesterone (P), corticosterone (B) and delta 4- androstenedione (A) were measured, (3) Variables studied were the ratio of plasma increments (delta) between precursors and end products, (4) Data were analysed by a step-wise discriminant analysis. Significant alterations in the metabolic pathway of F, B and A were demonstrated. The discriminant analysis showed that the addition of B pathway data did not improve the discrimination potency of the test performed on F pathway data. The combination of variates which provided the best discrimination was the logarithmic sum of delta 170HP/delta F at 15 and 30 min. It led to a 94% correct classification for normals and carriers.