15 beta-hydroxylated steroids may be diagnostically misleading in confirming congenital adrenal hyperplasia suspected by a newborn screening programme

In a Swiss screening programme for detection of congenital adrenal hyperplasia (CAH), 27 of over 120,000 newborns examined from 1992 to 1994 were further studied because of persistingly high 17 alpha hydroxyprogesterone (17OHP). Out of 27, 11 were later confirmed to have CAH by specific gas chromatography of urinary steroids and ACTH test at age 3-4 months. Of 27, 11 were born at term (7 confirmed 21-hydroxylase deficiency, one 11 beta-hydroxylase deficiency). Out of 27, 16 were preterm newborns. Of them, only 2 were confirmed to have CAH (one 21-, one 11 beta-hydroxylase deficiency). In 3 cases with high 17OHP, but later not confirmed CAH, what appeared to be a pregnanetriolone peak in the gas chromatograms was shown to be 3 beta, 15 beta, 17 alpha-pregnenetriol. This compound may be misleading in confirming the diagnosis of CAH. 15 beta-Hydroxylated compounds occur in fetuses, neonates, and amniotic fluid. Since human tissues do not have 15 beta-hydroxylating capacity, their origin is unclear. However, since some bacteria (Bacillus megatherium) and mycelial fungi (fusaria) are known to hydroxylate steroids in position 15 beta, it is likely that this compound is formed by micro-organisms in the enterohepatic circulation of newborns or their mothers. For the confirmation of the diagnosis of CAH in cases suspected by screening, later ACTH stimulation and specific steroid analysis are necessary.