Idiopathic hyperaldosteronism: analysis of aldosterone synthase gene.

We analyzed the CYP11B2, the gene encoding aldosterone synthase, in mononuclear leukocytes in eight patients with primary aldosteronism due to zona glomerulosa hyperplasia (idiopathic hyperaldosteronism) and compared the results with aldosterone-producing adenomas. In idiopathic hyperaldosteronism, aldosterone synthase activity was significantly increased in accordance with gene expression (P < 0.05), compared with aldosterone-producing adenomas. No genetic mutations were found in coding regions of DNA. The T (-344) C allele polymorphism was present in a similar frequency in the general population. In one patient with idiopathic hyperaldosteronism. de novo homozygous mutation in upstream of the 5' flanking region C (-463) T was detected, which cannot be explained by polymorphism. The pathophysiological significance of this mutation for aldosterone hypersecretion is not known. There were no mutations in the known promoter sequences for angiotensin II related cis-segments. Possible contribution of co-regulators for angiotensin 11-induced signalling pathway is discussed.