18-hydroxycorticosterone, 18-hydroxycortisol, and 18-oxocortisol in the diagnosis of primary aldosteronism and its subtypes.

CONTEXT: Diagnosis of primary aldosteronism (PA) is made by screening, confirmation testing, and subtype diagnosis (computed tomography scan and adrenal vein sampling). However, some tests are costly and unavailable in most hospitals. OBJECTIVE: The aim of the study was to evaluate the role of serum 18-hydroxycorticosterone (s18OHB), urinary and serum 18-hydroxycortisol (u- and s18OHF), and urinary and serum 18-oxocortisol (u- and s18oxoF) in the diagnosis of PA and its subtypes, aldosterone-producing adenoma (APA) and bilateral adrenal hyperplasia (BAH). PATIENTS: The study included 62 patients with low-renin essential hypertension (EH), 81 patients with PA (20 APA, 61 BAH), 24 patients with glucocorticoid-remediable aldosteronism, 16 patients with adrenal incidentaloma, and 30 normotensives. INTERVENTION AND MAIN OUTCOME MEASURES: We measured s18OHB, s18OHF, and s18oxoF before and after saline load test (SLT) and 24-h u18OHF and u18oxoF. RESULTS: PA patients displayed significantly higher levels of s18OHB, u18OHF, and u18oxoF compared to EH and normal subjects; APA patients displayed s18OHB, u18OHF, and u18oxoF levels significantly higher than BAH patients. Similar results were obtained for s18OHF and s18oxoF. SLT significantly reduced s18OHB, s18OHF, and s18oxoF in all groups, but steroid reduction was much less for APA patients compared to BAH and EH. The s18OHB/aldosterone ratio after SLT more than doubled in EH but remained unchanged in APA patients. CONCLUSIONS: u18OHF, u18oxoF, and s18OHB measurements in patients with a positive aldosterone/plasma renin activity ratio correlate with confirmatory tests and adrenal vein sampling in PA patients. If verified, these steroid assays would refine the diagnostic workup for PA.

Glucocorticoid remediable aldosteronism: low morbidity and mortality in a four-generation italian pedigree.

Glucocorticoid remediable hyperaldosteronism (GRA) is a monogenic form of inherited hypertension caused by a chimeric gene originating from an unequal cross-over between the 11 beta-hydroxylase (CYP11B1) and aldosterone synthase (CYP11B2) genes. GRA is characterized by high plasma levels of aldosterone (regulated by ACTH) with suppressed plasma renin activity and the production of two rare steroids, 18hydroxycortisol and 18oxocortisol. Affected patients usually show severe hypertension and an elevated frequency of stroke at a young age. Affected women have a high risk of developing preeclampsia during pregnancy. Here, we describe a 5-generation pedigree from Sardinia in which the presence of the chimeric gene is demonstrated in 4 generations. This family displays a mild phenotype with average blood pressure levels of 131/86 mm Hg for GRA+ patients. The occurrence of stroke is very low, and preeclampsia was not observed in 29 pregnancies from 8 GRA+ mothers. We investigated whether the cross-over site (between the CYP11B1 and CYP11B2 genes) or biochemical characteristics could explain this phenotype. The cross-over site was located at the end of intron 3, in the same region as described in other families. We found a significant correlation between blood pressure and 18hydroxycortisol, 18oxocortisol, and plasma aldosterone levels, but not with kallikrein. However, none of the biochemical or genetic parameters investigated could explain the mild phenotype of the family.