Familial Hyperaldosteronism Type II

Abstract

As originally defined, the term familial hyperaldosteronism type II (FH-II) refers to the occurrence in families of at least two members with primary aldosteronism (PA) that is not glucocorticoid suppressible and not associated with the hybrid CYP11B1/2 gene mutation responsible for familial hyperaldosteronism type I (FH-I, glucocorticoid-remediable aldosteronism). FH-II appears to be much more common than FH-I and is probably genetically heterogeneous. As in apparently non-familial PA, PA in the majority of patients with FH-II is due to either unilateral aldosterone-producing adenoma or bilateral adrenal hyperplasia which may be diffuse or nodular and responds favorably to unilateral adrenalectomy (for unilateral forms) or specific medical treatment antagonizing aldosterone action. So far, the only gene found to be mutated in the germ line of affected members of families with PA (after exclusion of FH-I by genetic testing for the hybrid gene) is KCNJ5, encoding a potassium channel, but this appears to be a rare cause of familial PA. The search for other underlying genetic mutations is ongoing.