Background: In premature and small-for-date infants, immature adrenal enzyme activity, adrenal stress responses and impaired hepatic clearance may lead to mild to moderate false-positive increases of steroid hormone precursors. This complicates screening programs for congenital adrenal hyperplasia (CAH) in these patients.
Objective and hypotheses: We present a preterm female infant (born at 33 weeks of gestation) whos newborn screening 55 h after birth revealed abnormally high concentrations of 17α-hydroxyprogesterone (176 nmol/l, ref. <88 nmol/l). Subsequent second tier steroid hormone profile analysis was suggestive for 11β-hydroxylase deficiency, the second most common form of CAH (11-desoxycortisol 962 nmol/l, ref. <17 nmol/l; androstendion 129 nmol/l, ref. <17.8 nmol/l).
Methods and results: Further detailed workup did not reveal any clinical features of androgen or mineralocorticoid excess, such as virilization or hypertension, at that time. Additional confirmatory blood samples were collected, and hydrocortisone treatment was initiated. Unexpectedly, all subsequent blood samples revealed a normal steroid hormone profile, and sequencing of the coding region of 11β-hydroxylase (CYP11B1) was normal. Re-analyses of the initial screening blood sample confirmed previous abnormal results. A confusion of patients and sample identity as well as drug-induced 11β-hydroxylase-inhibition (i.e. etomidate exposition) was excluded. Hydrocortisone replacement therapy was ceased, and an ACTH stimulation test that was performed 8 weeks later was normal.
Conclusion: Mild and unspecific increases of different steroid hormone precursors are well known in preterm and small-for-date infants. However, some patients may present with excessive false-positive increases of steroid hormone precursors, transiently completely mimicking a specific adrenal enzyme deficiency. This has to be taken into consideration when interpreting steroid hormone profiles of such patients.
10 - 12 Sep 2016
European Society for Paediatric Endocrinology