Diagnosis of glucocorticoid-remediable aldosteronism in primary aldosteronism: aldosterone response to dexamethasone and long polymerase chain reaction for chimeric gene.
Aldosterone suppression by dexamethasone, and high 18-hydroxycortisol and 18-oxocortisol levels are used to differentiate glucocorticoid-remediable aldosteronism (GRA) from other forms of primary aldosteronism. These methods are time consuming, expensive, and impractical for large studies. Moreover, diagnosis of GRA requires a confirmatory genetic test. We evaluated 117 patients with primary aldosteronism referred to our centers by the use of a long PCR technique to reveal the chimeric gene of GRA. In 60 of 117 patients, the response of aldosterone to dexamethasone (2 mg/day for 4 days) was also assessed. None of our patients, including 2 pairs of siblings, was positive for the chimeric gene. The results of long PCR were confirmed by Southern blotting. Despite a negative genetic test, 6 patients (1 with aldosterone-producing adenoma and 5 with idiopathic hyperaldosteronism) had plasma aldosterone suppressed by dexamethasone (i.e. < or = 2 ng/dL). Of 117 patients, 43 were identified as having aldosterone-producing adenoma and 74 as having idiopathic hyperaldosteronism. In our experience, the long PCR technique is a reliable and simple test to at least exclude GRA in patients with primary aldosteronism. A short term dexamethasone suppression test of aldosterone can be misleading in identifying GRA. The prevalence of GRA in primary aldosteronism remains to be established.
Mulatero
P
P
Department of Medicine and Experimental Oncology, University of Torino, Italy.
Veglio
F
F
Pilon
C
C
Rabbia
F
F
Zocchi
C
C
Limone
P
P
Boscaro
M
M
Sonino
N
N
Fallo
F
F
D000328:Adult; D000368:Aged; D003864:Depression, Chemical; D003907:Dexamethasone / Q000627:therapeutic use*; D003937:Diagnosis, Differential; D005260:Female; D005938:Glucocorticoids / Q000627:therapeutic use*; D006801:Humans; D006929:Hyperaldosteronism / Q000188:drug therapy* / Q000235:genetics; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods*; D011993:Recombinant Fusion Proteins / Q000235:genetics*
D005938:Glucocorticoids; D011993:Recombinant Fusion Proteins; D003907:Dexamethasone