Inherited Forms of Primary Hyperaldosteronism: New Genes, New Phenotypes and Proposition of A New Classification

Primary aldosteronism is a common cause of endocrine hypertension. It results from the excess production of aldosterone by the adrenal cortex and is related to increased morbidity and mortality. Most cases of PA are sporadic but inherited patterns of the disease have been reported in the literature. Four forms of familial hyperaldosteronism (FH-I- FH-IV) are currently recognized, and the genetic basis has been clarified in recent years. In FH-I patients, aldosterone excess is produced by a CYP11B1/CYP11B2 fusion gene and it is suppressed by glucocorticoid treatment. FH-II is caused by mutations in the inwardly rectifying chloride channel CLCN2. FH-III is caused by mutations in KCNJ5, a gene coding for an inward rectifier K+ channel and mutations in the T-type calcium channel subunit CACNA1H cause FH-IV. In this review we summarize the knowledge on inherited forms of primary aldosteronism, the genetic alterations that cause them and the implications it may have for the classification. Based on current evidence, we propose the term "familial hyperaldosteronism" to refer only to inherited forms of primary aldosteronism with a known genetic basis.